Using the theory of constraints in project management. Theory of Constraints for IT project management using the “Critical Chain” method. Buy manual cultivator tornado in obi

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1 Federal state budget educational institution higher vocational education"St. Petersburg State University of Architecture and Civil Engineering"

The analysis of the features of the Theory of Constraints of Systems (TOS) and the critical chain method proposed by E. Goldratt in the field of construction scheduling has been carried out. The prerequisites for the formation of TOS are revealed. The fundamental causes (within the framework of the general philosophy of TOC) leading to the failure of the deadlines for construction projects, exceeding their original budgets and changing the content are analyzed. It has been established that such a factor is Murphy's laws, which are enhanced by multitasking, a defect in the control mechanism, student syndrome and Parkinson's law. Held comparative analysis the critical path method and the critical chain method proposed by E. Goldratt according to 10 main provisions. On a practical example, the results of scheduling by these two methods are compared. It was revealed that the critical chain method allows designing construction schedules 16% more efficiently than the critical path method.

systems constraint theory

critical path method

critical chain method

1. Goldratt E.M. Critical chain: per. from English. E. Fedurko. - Minsk: Potpourri, 2013. - 240 p.

2. Goldratt E.M., Cox D. Purpose: The process of continuous improvement: per. from English. E. Fedurko. - Minsk: Potpourri, 2014. - 400 p.

3. Detmer W. Goldratt's Theory of Constraints: A systematic approach to continuous improvement: Per. from English. U. Salamatova; 2nd ed. - M.: Alpina Business Books, 2008. -444 p.

4. Lich L. On time and within the budget: Project management according to the critical chain method: Per. from English. U. Salamatova; 2nd ed. – M.: ALPINA PABLISHER, 2014. – 352 p.

5. Rechkalov V. Project management using the Critical Chain method [Electronic resource] // TOCPEOPLE: [website]. ).

6. Stelth P., Le Roy G. Projects’ Analysis through CPM (Critical Path Method) // School of Doctoral Studies (European Union) Journal. July, 2009. No. 1. Pp.10-51.

The Theory of Constraints (TOS) was formulated and substantiated by the Israeli scientist Eliyahu Moshe Goldratt in the 1980s. He actively developed and implemented it in the field of production, project management and even educational processes. The theory revolutionized the business environment and received a large number of followers who took up its further improvement. Among the best known are Lawrence Leach and William Detmer.

aim this study is to establish the features of the application of TOC and the critical chain method following from it to the scheduling of construction projects.

This work is based on the works of E. Goldratt, L. Leach, W. Detmer on the theory of constraints and its use in project management. The study was conducted using system analysis and comparison of phenomena and results.

The main prerequisites for the formation of TOS were first identified in the book by E. Goldratt “The Goal: The Process of Continuous Improvement”, which was published in 1984. The following statements are of interest for the field of construction project management and scheduling:

"A system of local optima is not at all an optimal system". Here, E. Goldratt focuses on the fallacy of the traditional approach to understanding the performance of the system, in which it is believed that maximizing the performance of each component (link) leads to maximizing the results of the entire system as a whole;

"Narrow links dictate the level of capital tied up, as well as system performance". The performance of the system is determined by the performance of the "bottleneck" ("bottleneck"), which acts as a constraint. Therefore, to increase the efficiency of work, it is enough to increase the productivity of one link, which will automatically reduce the level of associated capital, as well as operating costs, by accelerating the passage through the chain of events.

In the same book (“Goal: a process of continuous improvement”), E. Goldratt formulates a sequence of steps for optimizing and balancing the system:

Step 1. Find system limitations;

Step 2. Decide how to effectively use the system's limitations;

Step 3. Coordinate all other actions with this decision;

Step 4. Increase the throughput of the restriction;

Step 5. If at the previous stage the bottleneck was eliminated, then return to step 1.

Theory of Constraints belongs to the category of methods built on logical procedures, including JIT (Just in Time) and TQM (Total Quality Management). These management philosophies complement each other in many ways. Although in their pure form they are not very applicable to project management. But the convergence of individual elements of these theories allows us to take a huge step in improving this process.

The main reason leading to delays in project delivery, budget overruns and content cuts, and, consequently, a decrease in income from their implementation, is the uncertainty of the factors and conditions in which the project will be implemented. Otherwise, E. Goldratt calls this reason "Murphy", i.e. Murphy's laws: "Whatevercangowrong, will" (anything that can go wrong is sure to go wrong).

In practice, people always strive to take into account this uncertainty by providing a safety net when estimating the duration of operations, which, according to the observations of E. Goldratt, can reach 200%. Nevertheless, successfully, i.e. on time and in compliance with the planned profitability indicators, only 1/3 of the projects are completed.

Strengthening the effect of Murphy's laws up to the impossibility of eliminating their consequences is due to:

1. Loss of focus of performers due to the simultaneous execution and control of several tasks. Multitasking leads to an increase in the duration of work due to the "jumping" from one process to another. L. Leach gives an example when the performer during the day sequentially works on three tasks, the duration of each of which, subject to continuity, is one week. With daily simultaneous execution of three processes, their duration increases to three weeks, which provokes a delay in subsequent related tasks (Fig. 1). In addition, it is necessary to add time to return to the process after it has been stopped, i.e. to restore details, especially if the task is accompanied by complex mental work;

Fig.1. The impact of multitasking on the duration of a single activity in a project

2. A defect in the control mechanism used to measure the progress of the project. A traditional project progress report typically reflects the following pattern: the first 90% of work takes 10% of the time, and the last 10% takes the remaining 90% of the time. In this situation, timely detection of project sites where Murphy's law has manifested itself and where corrective actions are required is impossible;

3. Student Syndrome: "There is nowhere to rush, so we start at the last minute." When a person believes that there is enough time to complete a task, the motivation to immediately start the process disappears. The reserve is exhausted before work begins, and the manifestation of Murphy's law cannot be compensated for in the future, and this leads to a delay in the project;

4. Operation of Parkinson's law: "work expands to fill all the time remaining until its completion." E. Goldratt notes: “With successive elements, deviations in time are not averaged. Lateness is cumulative, while time gains are not cumulative. The executor who completed the task earlier than the deadline never declares this, but takes actions to improve the work performed and deliver the results according to the plan. Delays that accumulate from link to link manifest themselves differently. Consequence: The completion date of the project is pushed back by the sum of these delays.

These factors lead to the full use of the pledged insurance, no matter how large, well before the completion date of the project.

To reduce the impact of these impacts, E. Goldratt suggested using the critical chain method (CriticalChainProjectManagement - CCPM) in project management. The general algorithm corresponds to the previously indicated 5 steps of TOC.

The constraint of the project, its bottleneck, is the critical path, i.e. the longest sequence of dependent project items that have no slack.

The critical path is based on time constraints, predetermined solely by the technological connections of tasks. This does not take into account the dependence of the elements from the point of view of their performer. If the resource is busy on one non-critical path, and in parallel its work is required on another non-critical path, a delay is provoked, which leads to a change in the critical path. Those. even if the elements in the project are not technologically related, they may be dependent on the same resource. Relationships of elements in terms of both technology and the executing resource are taken into account in the critical chain. E. Goldratt defines it as the longest chain, consisting of path-dependent segments and resource-dependent segments.

The main difference between the critical path method and the critical chain method is that in the critical path the uncertainty is taken into account within each task, and in the critical chain it is taken out separately at the end of the project (Fig. 2). At the same time, it should be noted that if the project has no resource (performer) restrictions, then the critical path and the critical chain are the same.

Fig.2. Graphical comparison of critical path and critical chain methods

A comparison of the methods of the critical path and the critical chain for a number of indicators is given in Table 1.

Table 1

Comparison of critical path and critical chain methods

	Name of the comparison indicator	Critical Path Method	Critical chain method
	Definition	The critical path is the longest sequence of dependent project elements that do not have slack.	Critical chain - the longest sequence of dependent elements of the project, consisting of segments that do not have a slack, taking into account restrictions on the use of resources
	Constraint static	The critical path may change during the course of the project, depending on the actual completion dates of a particular task.	The critical chain does not change during the implementation of the project
	Fixed dates	The critical path determines the start and end dates of the project.	The critical chain captures only the completion date of the project (after adding the project buffer). The start of the project can also be determined by a non-critical task
	Determining the duration of tasks	The duration of the tasks is estimated by a calculation or expert method, taking into account the "safety net" based on previous negative experience	The duration of tasks determined by the calculation or expert method, taking into account the "safety net" based on previous negative experience, is reduced by 50%
	Accounting for uncertainty	Uncertainty is taken into account indirectly when determining the duration of each individual task	Uncertainty is taken into account explicitly in the supply buffers and the design buffer
	Schedule management	In order for the project to be implemented according to the schedule, each individual task must be completed on time.	In order for the project to be implemented in accordance with the schedule, it is necessary to control the protective buffers of the project, which absorb the coefficient of uncertainty of each individual task.
	Schedule control	The start and end dates of each task are tracked. Each delay affects the completion date of the project, so they must be carefully monitored	Start and end dates for individual tasks are not critical. It is necessary to carefully monitor the state of protective buffers and the activity of their consumption.
	Project Progress Evaluation	To assess the progress of the project for a certain date, a fixed date for the completion of one or another stage of the project (milestone) is used	All completion dates for a particular project stage (milestone) are floating. To assess progress, it is enough to determine whether the stage is in the completion stage, and also analyze the consumption of the protective buffer to indicate the probability of completion of the stage by a certain date
	Time slack on non-critical paths	The slack that exists on non-critical paths is not important and is not tracked.	To protect the critical circuit, non-critical paths should have feed buffers whose status is constantly monitored.
	Attitude towards multitasking	The progress of each ongoing project (task) is important, so the multitasking mode when using resources is preserved	Multitasking in the work of resources is limited up to a delay in the start of the implementation of other parallel projects (tasks)

The reliability of the project completion date in CCPM is ensured by adding buffers to the schedule to protect the critical chain from the effects of Murphy's Laws.

CCPM assumes two types of buffers:

A path merge buffer that is added at the point where a non-critical chain meets a critical one. This ensures the timely start of work at the stage as part of the critical chain in the event of a failure on a non-critical element;

A project buffer placed at the end of a project. It allows you to compensate for the delays that appeared on the critical chain.

There may be several options for the critical chain in one project, depending on the decision made to eliminate competition for resources. And this, in turn, is an optimization problem. But E. Goldratt does not attach much importance to the form of resource allocation due to the lack of a “real difference” that exceeds the degree of uncertainty in the project, which is extinguished in the buffers being pledged.

A comparison of several options for a simple schedule for the construction of two cottages with an enlarged breakdown of work into 6 stages showed that the critical chain method allows you to create a schedule that will be 16% more efficient than the critical path method (see Fig. 3, 4).

The spread of values ​​when comparing three graphs using the critical chain method, depending on the option to eliminate the conflict of resources, does not exceed 4%, which confirms the opinion of E. Goldratt about the inefficiency of optimization and allows using any form of resource leveling when planning.

The comparison results are displayed in table. 2.

table 2

Comparison of graphs generated by the method of critical path and critical chain

Name	Number of days
Critical Path Method
Before resource leveling
After alignment (two options - using the built-in MS Project function)
Critical chain method
Alignment using the built-in function of MS Project (option 1)
Manual alignment (option 2)
Manual alignment (option 3)
Comparison of graphs using the critical chain method
Comparison - option 1 / option 2
Comparison - option 2 / option 3
Comparison - option 3 / option 1
Comparison of the critical path method and the critical chain method (by maximum values)

Rice. 3. Project schedule according to the critical path method

Rice. 4. Project schedule according to the critical chain method - option 1

Based on the results of the study, the following conclusions can be drawn:

The performance of any system, incl. and construction and investment project, is determined by the performance of the weakest link, which acts as a constraint; in a construction project, this constraint is the critical path;

Due to the constraint, as well as the uncertainty inherent in the operation of the system, the vast majority of projects experience missed deadlines, budget overruns, and scope cuts;

The critical path method takes into account the time constraint of the project, but does not take into account resource constraints (executors), therefore, in construction projects, the use of the critical chain method is more reasonable (an improvement in the schedule by 16% was recorded);

The effectiveness of optimization algorithms and methods is doubtful, their application is a laborious process that does not significantly improve the results of scheduling (a simple example revealed differences between the schedule options that do not exceed 4%).

Reviewers:

Bolotin S.A., Doctor of Technical Sciences, Professor, FGBOU VPO "SPbGASU", St. Petersburg.

Vatin N.I., Doctor of Technical Sciences, Professor, FGOU VPO "SPbSPU", St. Petersburg.

Bibliographic link

Kotovskaya M.A. FEATURES OF THE THEORY OF LIMITATIONS OF GOLDRATT SYSTEMS AND THE CRITICAL CHAIN ​​METHOD IN THE FIELD OF SCHEDULING OF CONSTRUCTION PROJECTS // Modern Problems of Science and Education. - 2014. - No. 4.;
URL: http://science-education.ru/ru/article/view?id=14374 (date of access: 01.02.2020). We bring to your attention the journals published by the publishing house "Academy of Natural History"

Whether you work in the service industry, industry, IT technology, design or marketing, project management is an indispensable part of your business. Every company is constantly changing. And in order to cope with the problems that have arisen and solve them on time, you need to manage changes as a project.

Every project has a goal, a beginning and an end. Only the end of the project leads to the opportunity to earn new money. Therefore, the most important question becomes: can we meet the deadline and within the allocated budget? The traditional approach to project management looks like this: the project is divided into separate tasks, which are assigned calendar start and finish dates. A well-designed plan is supposed to be easy to implement. But how in this case to take into account all the unforeseen circumstances? Is it possible to effectively initiate, plan and control projects based on intuition alone? How, then, to reduce the risks? At the same time, it is known that even well-planned projects, in the course of their execution, are knocked out of the budget and calendar dates.

Managing a project means being able to deal with uncertainty. Projects are never similar to each other and they always contain some probability of events. But the modern market requires projects to be completed on time and in full. Therefore, when implementing most projects, only experience and common sense are not enough; an appropriate project management methodology is also required.

The critical chain method, based on the principles of the Theory of Constraints, allows you to effectively manage uncertainty in projects. Using the project buffer tool helps to receive timely information about those tasks that are now leading to delay and jeopardizing the budget. At this seminar, you will receive a tool that will allow you to prioritize, determine the actual tasks of the project, and accurately allocate resources.

The target audience: managers who manage a multitasking environment, project managers, marketers, designers, IT specialists.

Target: master the critical chain method and Scrum for project management.

In this seminar you:

• Familiarize yourself with the TOC and Agile approach;
• learn all about the critical chain method and Scrum for project management;
• learn how to plan the project's critical chain and scrum sprint;
• understand how to manage a project using the project buffer;
• get ready-made solutions for managing uncertainty in the project.

Seminar program

1st day. Project environment and management behavior in project management

1. Undesirable phenomena in projects: failure to meet deadlines, repeated postponement of completion dates, budget overruns, rush and processing, cuts in functionality and specifications, constant lack of resources, competition for them.
   • Problems that hinder project management.
   • Features of project management of the participants of the seminar.
   • The main characteristics of the project management environment: uncertainty, multitasking, local performance indicators.
2. Typical behavior for the project management environment: drawing up detailed project schedules, monitoring the accuracy of fulfilling obligations on task deadlines, early launching projects for execution, “bad” multitasking.
3. Introduction to TOS. Principles and assumptions.
4. The root conflict of the design environment.
5. Major misconceptions in project management:
   • a game that demonstrates the impact of multitasking;
   • discussion of student syndrome and the Parkinson effect.
6. Competitive advantage in the project environment (time reliability, quality assurance and budget compliance).
7. The concept of the critical chain (CCPM) and its difference from the concept of the critical path.
8. Philosophy Agile. Scrum concept for project management.

2-3rd day. Critical chain project management

1. Management setting and the introduction of new performance indicators that allow you to see the dynamics of income from projects.
2. Reducing multitasking:
   • freezing of a part of ongoing projects;
   • accelerate the implementation of the remaining projects;
   • defrosting projects as the previous ones are completed, "virtual drum";
   • launch of new projects.
3. Tool Kit (complete preparation of the project for launch):
   • preparation of projects in accordance with priorities;
   • determination of the scope of work for the preparation of projects;
   • exclusion of the risk of losing customers due to the late launch of projects.
4. Planning:
   • building good PERT plans;
   • definition of a critical chain, taking into account the limited resources, the concept of a project buffer, the concept of a feeding buffer;
   • separation of the project portfolio.
5. Project execution management:
   • daily reporting on the implementation of tasks, communication issues;
   • ensuring the implementation and preparation of tasks in accordance with established priorities;
   • timely adoption of corrective measures by top management;
   • regulation of execution speed at the project integration point.
6. Elimination of project delays due to the fault of clients.
7. Placement of orders with subcontractors:
   • control of work performance;
   • use of effective incentives for on-time performance by the contractor.
8. Selling the reliability of project completion on time.
9. Workload control: regardless of sales growth, the company always meets deadlines.
10. Continuous improvement process:
    • report on the reasons for delays;
    • analysis of reasons for delays;
    • initiation of projects to improve performance.
11. Power extension:
    • identification of resources responsible for delays in projects;
    • ensuring the timely availability of the necessary labor resources.
12. Implementation competitive advantage"early delivery":
    • formation of a "bonus market";
    • development of a bonus offer;
    • sale of "early delivery";
    • fast completion of the project.
13. Project management software for TOC and Scrum.
14. Organization of work in the project according to the Scrum method:
    • planning and prioritization of work;
    • Product Owner and Scrum Master roles
    • holding scrum meetings;
    • holding a retrospective.
15. Sharing of CCPM and Scrum methods.
16. Examples of the application of the critical chain method and Scrum in enterprises of various industries.

There is nothing more permanent than something temporary. In project management, the project itself can seem like something small, easily manageable. But the week turns into a month, a month into a quarter, deadlines are burning, and a small, temporary project grows into a monster that devours time and resources.

We have already considered different project management methodologies in past reviews. You can familiarize yourself with,, and.

Today we will talk about:

• how to estimate and predict project timeline from scratch in CCPM?
• what rules do you need to know for the correct calculation of time?
• Why is the critical chain method the choice of hundreds of successful companies?
• how to introduce the critical chain method (CCM) in your company?
• How can I implement CCPM using the Worksection service?

Origin of methodology

For the first time the concept of "critical chain method" sounded in the book. Eliyahu's predecessor books presented separate ideas and techniques that later merged into CCPM: from the drum-buffer-rope method (DBR) to the theory of constraints (TOC). The latter eventually transformed into one of the most popular project management methodologies.

TOC (Theory of Constraints) is a project and organization management methodology created by Eliyahu Goldratt. TOC is based on finding and managing the key limitation of the system, which determines its effectiveness.

DBR (drum-buffer-rope) is one of the methods of the theory of constraints, aimed at "expanding" the constraints of the system, subordinating production to the most efficient use of the constraint. It is built on the use of a work schedule for restriction (drum), which contains a protective buffer that protects against downtime (buffer), and on the organization of a mechanism for the timely release of work into production.

Already in 1997, Goldratt, the creator of the theory of constraints, realized that in order to implement the methodology in life, it must be as simple and understandable as possible. User-friendly approach 20 years after the creation of the theory of constraints resulted in its business version - CCPM - Critical Chain Project Management. And since everything new is a well-forgotten old, CCPM turned out to be similar both to the TOC of the same Goldratt, and to PERT method. The latter was developed to calculate the expected duration of the project or the time to achieve tasks at certain stages of it, and has been used in modifications in many organizations.

PERT is both a method and a network planning tool. The method allows you to estimate the duration of tasks based on 3 estimates with their further use when building a diagram.

All previous methods developed before the beginning of the second half of the 20th century are obsolete. The critical chain method was the first effective method project management after the development of PERT, and after all, 45 years have passed since the invention of the latter!

The development of CCPM did not end with the release of four books that popularly talk about the implementation of methodology in business project management. Dozens of books on project management appear on the shelves every year, which in one way or another use the critical chain method (we recommend), and the British company Goldratt, created by the founder of the Goldratt method, offers services for the implementation of CCPM in the project management of firms.

Estimating project timelines from scratch using CCPM

When starting to work on the critical chain (CC) of the project, it is impossible to ignore the issue of assessing the timing of tasks and the duration of the project as a whole.

Calculating project timelines is more difficult than it might seem at first glance. If you directly ask performers to indicate the average time for which the task will be completed, they will, at best, indicate the time with a margin, and at worst, they will assure that the task will be completed quickly and expose the entire project to a blow.

To avoid this common mistake, you need to consider the following rules:

• Timing should be estimated based on 100% artist download. This, firstly, will keep all performers in good shape, preventing downtime, and, secondly, it will significantly reduce the overall duration of the project.
• part of the estimated time should be allocated to buffers- you can calculate this part according to a simple scheme: the total estimated time is halved, and the second half becomes a buffer;
• the difference between the average and probable time estimates should be significant − use a factor of 2x or more(more on this later). This will help avoid the formal distinction between different types timing and is useful when using the PERT method.

It is convenient to calculate the execution time of individual tasks in a project and its completion using the PERT method. But timing based on 3 times (best, likely and worst) does not include the possibility of failures and delays. The most important tool for dealing with them is the project buffer, which is placed between the completion date of the last task and the project completion date. Thus, the length of the critical chain, which means the project time is calculated from the very first task within the CC to the start of the project buffer.

In the Worksection service, the calculated deadlines can be entered directly into the assigned tasks and subtasks, respectively.
It is worth deciding in advance whether deadlines for tasks will be indicated with buffer or related tasks will have start dates shifted.

In addition to the project buffer, it is important to take into account the feed buffer (path merge buffer)- the margin of time that is located between the stage of work of the non-critical chain and the stage of work within the framework of the critical chain. Typically, the length of such a buffer is 50% of the length of the non-critical circuit to which it is added.

Deciphering PERT as a Method and Chart

Speaking about the critical chain method, it is impossible to ignore one of the popular network planning methods - PERT (Program Evaluation and Review Technique).

It was first used on the Polaris submarine in 1958 to build a schedule that included more than 3,300 contractors. This shows the specificity of PERT as a network planning method for large projects (on average, above 300-400 operations).

According to the method, the duration of each task has limits, which are calculated according to the statistical distribution.

The key point is that 3 values ​​​​are used at once to estimate the time of each task:

1. optimistic (best);
2. expected (probable);
3. pessimistic (worst).

The longer the total duration of the project, the higher the cost of an error: the number of variables increases, the statistical errors in time estimates increase, and the risk of changes in the key elements of the plan appears. To deal with these problems, you can look at the surfer. He constantly balances to stay on the crest of the wave on the board as long as possible. There is no one correct body position!

This is what inspired the creation of "traveling wave planning". So, the project of Buns Landsdorp Mars One assumed the duration of the Mars colonization project in 22 years - from 2011 to 2033. Each stage took 1-2 years, and was scheduled on the official website of the project. But the lack of experience in solving the tasks and the uniqueness of the project led to the fact that the expected timeline shifted. The expected duration of the project has grown to 24 years!

Why do we need three whole values ​​at all? They are used in the mathematical formula for estimating the weighted average completion time of an operation (project):

tE = (tO + 4tM + tP) / 6

• where tE is the operation (project) time;
• tO is the optimistic (best) time;
• tM is the expected (probable) time;
• tP is the pessimistic (worst) time.

As with any calculation, errors are possible here. The PERT method, by its very nature, underestimates the estimated duration of the project task.
This means that the more tasks there are, the more errors you may encounter.

For the same reason, it would be correct involvement of experts in the project area, which can reduce the spread between the three estimates of the project time, and thereby reduce the error rate.

This is what a PERT chart looks like

The PERT chart represents the tasks that need to be completed to complete the entire project. It consists of elements:

• Arrows- determine the direction from one task to another, and indicate the events that should occur;
• Rooms- are assigned to each task;
• Days/weeks/months- are indicated both under each task based on the results of applying the PERT formula, and in a horizontal schedule that determines the time within which all project tasks are completed.

How to create a working PERT chart? Here are 4 simple steps:

1. Make a list of milestones (large sections of the project) and tasks within the milestones of the project. Write them down as tasks in the project.
2. Use the PERT formula to determine the time required for each event to complete. Specify start and end dates for tasks.
3. Define dependencies between tasks to create links. Consider buffer zones.
4. The lines in the diagram should come to tasks that are related to the completion of the previous one. Visualize the diagram on paper or whiteboard in a team meeting.

It is not necessary to draw up a schedule manually - you can use special software (for example,).

Advantages and disadvantages of the methodology

CCPM, like any other project management method, has its pros and cons. Whether you will use it to achieve the goals of the company or not depends on the format and size of the company, the scope of services or products provided, corporate culture and other factors.

So why do companies like American Express, Boeing Commercial Airplanes, Ford Motor Company and Heineken use the critical chain method in their daily work?

Benefits of CCPM:

1. time-balanced resource load - unlike the critical path method, you are not constrained by a rigid sequence of tasks or strict planning.
2. one task is performed per unit of time - it can be considered both a plus (there is no danger of task overlapping) or a minus, because the performer is subject to increased requirements for the ability to quickly switch between tasks and task chains.
3. it is easy to detect emerging delays and threats of disrupting project deadlines - thanks to buffers (project buffers, resource and time buffers and a feeding buffer), the project manager is able to “protect” the project completion date from task variations.
4. focusing resources on critical tasks - allows you to eliminate competition for resources within the project.
5. relieves such diseases of the project as "student syndrome", the use of multitasking, from the effects of Parkinson's and Murphy's laws.

In the case of Eurovision 2017, the available resources are enough to significantly save budget costs. So, the venue is the International Exhibition Center, which was opened in 2002. It fit perfectly into the existing concept of a television show attracting a large number of viewers.

So for every plus of the critical chain method there is a minus.

Disadvantages of CCPM:

1. increased project implementation time - this happens at the expense of time buffers, since when using the critical chain method, the key is the completion date of the entire project, and not the deadline for completing a separate task. In most cases, the longer a project takes to complete, the higher the cost.
2. increased requirements for the qualification of a project manager - for the successful implementation of CCPM, it is not enough to read a couple of books, you need practice and careful study on paper. Can't do without either.
3. the bulkiness of the critical chain method in a “dry” form - when creating a plan for CCPM, you have to take into account a dozen factors: tasks, deadlines, buffers, and much more. Even if the project manager sorts out these complexities, how to show management how it really works? After all, the original plan will change with further development project. And the main goal of the project is not the implementation of the plan (albeit a detailed one), but the effective achievement of the stated goals.
4. the need to form separate teams for each project stems from the impossibility of using one resource simultaneously in several different projects. In this regard, Oded Cowen, an international expert at TOC, noted that MCC is more suitable for large projects and enterprises, in particular, in the areas of installing telecommunications networks, repairing and re-equipping aircraft, and developing products for next-generation wireless technologies.

What project management issues do project managers not talk about?
Four barriers in the life of any organization that all project managers go through - or give up and the project does not reach the final stage.

• "Student Syndrome" - the more time is allotted to complete the task (including safety net), the later the person will begin to complete this task. The desire to put off completing a task until the last minute is explained by procrastination, laziness, and ill-conceived management. The latter can be combated by limiting the time to complete the task.

• Multitasking is the performance of several tasks at the same time, which usually leads to a failure of the planned deadlines or to a deterioration in the quality of the work performed. According to research by the University of Utah’s Department of Psychology, only 2% of people on Earth are able to effectively multitask. And the American Psychological Association has noted that constantly switching between tasks reduces productivity by up to 40% than if you completed them in a queue.

• Parkinson's Law - the amount of work tends to increase in order to fill the time allotted for its implementation.

• Murphy's Law - If something bad can happen, it will happen. The subconscious also knows about Murphy's law, so the project participants seek to insure themselves by laying a reserve of time and lengthening the deadline for completing the task several times.

Alternative View: Differences between Critical Chain Method (CCPM) and Critical Path Method (CPM)

Key differences between the critical chain method and the critical path:

1. the critical path in CPM has an "idealized" character, in CCPM the path is built taking into account resource constraints.
2. the main tasks of CPM are project planning, determination of the most priority tasks; The main task of the critical chain method is to complete the project as quickly as possible, taking into account resource constraints.
3. The critical path method is based on predicting the project timeline, while CCPM is based on the initial uncertainty of the duration of the work.
4. the critical path method is more suitable for determining the timing of the release of a product, and CCPM is more suitable for projects in which the deadline is already known.
5. The critical path method is based on a rigid task sequence, while the critical chain method is based on flexible planning.

There are two hard-pegged deadlines in CCPM − product launch and release dates(delivery of the project). Development and work with a chain of tasks is the main goal of the method. The critical chain is a sequence of project tasks. The implementation of the project itself depends on their implementation. The length of the critical path and the project completion date depend on the size of the tasks and resources for their implementation. In this, CCPM is similar to CPM (which is why they are so often confused): longest chain path - critical .

Lawrence Leach, in On Time and On Budget: Critical Chain Project Management, warns against a common mistake. Often, managers use the originally built critical chain as the basis of constraints for project execution. It would be more correct to build a new one on the basis of the primary chain, already taking into account resource limitations.

Virtual critical circuit
its properties are similar to the usual chain.
It is important to stay strong in a state of tension.
The strength of each chain is determined
strength of the weakest link.
If you hang a multi-ton load on a chain, where one link is made of wood, and all the rest are made of the strongest titanium, then it is better to move away,
because it will fall in the next second.

The most striking example of how the weak link destroys the entire project is the computer game No Man’s Sky. An entire marketing campaign was launched for it, tied to the dates of the major gaming exhibitions E3 2014 and 2015. They were strong links in the critical chain of the No Man's Sky Game Release, which earned the project high marks in the press in absentia and the title of "Best Original Game" and "Best indie game" even before release. One of critical links was the creation of a design document and, as shown negative feedback after the release of the product to the market, the weakest.

Boring gameplay, no original ideas and a slender game concept buried the hope of success. And even a powerful marketing campaign, ordering advertising in the largest specialized publications and good graphic design did not save from a complete failure in the market. So the weak link burst - the design document (a detailed description of the computer game being developed, the plot and essence of the project), the foundation of the foundations of the game project - and the whole chain crumbled, losing its meaning.

The No Man's Sky example shows that The strength of a chain is determined by the weakest links in it. The rules of real life also work for a conditional chain: strengthen the weak link and the critical chain will become viable. What is it for?

Comes into action theory of constraints (TOC), which reinforces the critical chain method. One of the rules of TOC is that a project can do as much work as allows you to make the weakest link in the chain. In simple terms, it is necessary to start work in accordance with the power of the weakest link.

In the case of No Man's Sky, having determined the dizdok as the weakest element, the developers had two ways:

• redistribute the load and increase the amount of resources for creating a development document;
• reduce the amount of resources spent on a marketing campaign and other links that take most of the resources.

No one will dispute the uniqueness of each project: goals, deadlines, resources, the degree of novelty, the scale of the company differ in each specific case, and it is impossible to create the only correct, 100% working scheme.

We offer a squeeze-a set of practical steps for using the MCC in individual project planning. They will be useful to you, even if you have already encountered CCPM in project work. If the MCC is new to you, a detailed checklist will be below. With its help, it is easy to build a project plan diagram using the critical chain method.

7 practical steps:

1. Explain to the team that will be working on the project the importance of protecting task duration and resource estimates from management. Unfortunately, the chaotic and fast execution of tasks can look spectacular, but not efficient, and become a real disaster for the project manager.
   In Worksection, you can assign the rights of each team member so that only the PM can set deadlines and budget, but he will prescribe this only after agreement and approval with the entire team.
2. Eliminate resource contention by load balancing. Thanks to this, the need to switch resources between tasks will also disappear.
   Notice uneven load you can in the People tab, where you can see how many tasks each individual performer has.
3. Plan tasks that do not depend from any other tasks, starting from project end date to its beginning!
   On the built-in Gantt Chart, you can specify which tasks are related and which are independent from others.
4. To permanently solve the resource unavailability problem, add resource buffers to the critical chain.
   You can specify with Tags which resources are needed for a task and control the load in the list of tasks.
5. Insert a design buffer at the end of the project to accumulate spare time (about 50% of the length of the entire critical chain).
   Specify it in the name of the project or root task. You can make the task "Final / Delivery of the project" and assign its Start Date to the day after all the tasks plus backup time. The same date should be announced to customers.
6. Calculate and arrange feed buffers for all paths that critical circuits depend on.
   This should be done before setting Start and End Dates for tasks.
7. Develop a working scheme for tracking the performance of performers in working on tasks. They should work as quickly as possible and not delay the delivery of the results of the work upon its completion.
   In the Reports section, you can select the By people format and track completed tasks for a selected period of time.

CHECK-LIST on the example of Eurovision 2017 and Lockheed projects

Creating a project plan in the form of a critical chain from scratch is not an easy task, but if you have a checklist for choosing the optimal CC path, everything becomes easier. If you were the organizers of the largest international Eurovision Song Contest in Ukraine, what would you need to do according to CCPM?

1. Determine all the tasks needed to complete the project.

This is a number of large blocks (advertising, technical support, security), which are divided into a number of small ones: advertising - on SMM, recording radio jingles, release of thematic TV programs; technical support - for the analysis of the riders of the artists, the search and selection of specialists, the creation of a single network of technicians; security - for briefing the police and the National Guard, planning street closures, organizing points with metal detectors.

2. Build the formed tasks into a logical chain, specifying the average value as the duration.

If your team is responsible for the organization of the Eurovision Song Contest, then you have won the state tender, and you have enough experience to determine the average duration of each of the tasks. So, the briefing of the police and the National Guard will take about a week - with a high-quality study of conflict situations and theoretical lectures, but it will take about 8 hours to block the streets during the opening ceremony.

3. Indicate the initial resources - performers, finances, material and technical base. Most companies have a base of specialists with whom it maintains links.

Therefore, the search and selection of specialists who will be engaged in the technical support of the Arena will first take place according to the already existing list. Before making a request, you need to update the material, technical and financial base in order to understand what specialists, in what quantity and under what conditions you can attract.

4. Identify possible resource conflicts - the fewer resources, the more such conflicts can occur during the life of the project. By changing the deadlines for completing tasks, completely get rid of resource contradictions. The resulting chain of interrelated tasks with resources and deadlines will be critical.

Two coordinators of volunteers at Eurovision in your team have 900 volunteers under their supervision. Moreover, each of them often works in two sectors. The ill-conceived use of such a powerful human resource can lead to confusion and low efficiency. Therefore, it is more logical to put down a schedule of shifts, according to which some of the volunteers will always be free and can be involved in solving "urgent" or small current tasks, such as the formation of packages with souvenir products for foreign delegations, verification of documents for press accreditation, etc.

5. Work through the resulting chain, reducing the duration to the maximum. This can be achieved by changing the priority and order of tasks in the diagram.

You can randomly arrange briefings for Eurovision volunteers: first aid, evacuation, conversation in English etc. But when selecting among the conditions, you already put “knowledge of English at a level not lower than intermediate”. And if not all volunteers will directly communicate with foreign delegations, then everyone may need to save a person's life. Therefore, we give priority to trainings in first aid, which we make mandatory, and remove the status of “mandatory” from the course of spoken language, which automatically frees up 2 days in the critical chain.

6. Add a project buffer at the end of the project life (up to 50% of the total CCPM duration).

Let's digress from Eurovision. Lockheed, which specializes in the creation of aircraft in the field of civil aviation, decides to launch a new project of an unmanned aircraft for aerial photography of hot spots in the Far East. The project date is quite clear - February 19, 2017. Having worked out a plan using the critical chain method, you understand that 1 year 3 months is enough for you to launch an experimental prototype.

Taking into account possible technological innovations, bureaucratic problems with the registration of the prototype and the novelty of the project in civil aviation, it is worth adding a project buffer of 9 months. As a result, you get a clean 2 years, during which you can confidently provide a working, and most importantly, a safe prototype, for which you will receive the necessary certification.

7. Make sure that all tasks are necessary to achieve the final goal.

It is Lockheed's policy to publicize the inner workings extensively, not least to publicize the company and make it more attractive to potential shareholders. But when developing a drone for aerial photography for a military order, you don’t need the “Advertising” task block to achieve the final goal. In the future, when you can adapt the device for civilian needs, this block of tasks will become relevant. The same goes for design decisions.

8. Add safety buffers - the same mechanism as in the design buffer, only for a single critical chain, not the entire project. It's an airbag for executives and teams working on projects with tight deadlines.

A clear example of howsaves the project from missed deadlines

Several departments of Lockheed are involved in the work on the drone, each of which is responsible for a separate aircraft unit. To perform their tasks within the framework of a common critical chain, the rule from clause 6 works - a security buffer of 50% of the duration of the critical chain to create a separate node unmanned vehicle will protect the project from problems over time.

9. Check the resulting critical chain for errors, resource and time conflicts.

On Habrahabr, a team of 7 people plus or minus two employees is considered optimal. And if there are 30 of them, as in the Lockheed project to create a drone? And if there are more than 1,000, as in the case of the Eurovision preparation project?

By substituting financial, material and technical resources, buffers and other variables into the formulas, the probability of error will increase significantly. That is why large companies, when introducing new management methods, involve coaches or entire teams who teach project management based on the methods of the critical path and the chain, as well as TOC in general.

Double check has not interfered with any plan yet (even if several days are allotted for it in the critical chain), and there is no need to talk about how much it will save resources if an error is detected early.

Critical Chain Project Management Plan

The critical chain plan is the basis for the exchange of information, thanks to which the actions within the critical chain are clear not only to the project manager, but also to other executors of the plan.

The project management plan includes:

1. detailed description of the content of the project- without understanding the specifics, importance of the project, its purpose, it is impossible to draw up a high-quality working plan for managing this project.
2. work breakdown structure for project execution- to create an unmanned vehicle for aerial photography and video shooting, the simplified hierarchy looks like this: first, you need to create the concept of the device, then you need to carry out all necessary calculations and only then build a prototype. If you change the order, the project will never reach its logical end.
3. a list of those responsible for performing tasks within a hierarchical structure- this is a project manager, specific departments of the company, specialists who are planned to be outsourced.
4. project schedule according to the critical chain method.

The specificity of large projects leads to additions to the plan. In addition to the immediate critical chain (project schedule with aligned resources), they add:

• separate subject plans for security, supplies, staffing, etc. In the International Standard for Project Management ISO 21500:2012 they are also called "subject groups". In the case of a drone being built by Lockheed, the substantive procurement plan will include the processes needed to acquire outsourcing services and electronic control systems for the drone, as well as to manage interactions with suppliers at the tender level and communication immediately after the conclusion of contracts.
• recommendations for the exchange of information in the project, rules for reporting, distribution and approval of documentation - for this, for example, standard reporting forms are created at large enterprises.
• specifications and standards– in the case of preparing catering for foreign delegations, these can be sanitary and hygienic and sanitary and anti-epidemic rules and regulations for enterprises Catering. They are important both from the point of view of food safety at the buffet table, and from the point of view of compliance with the tender conditions on the basis of which the catering was chosen.
• change management plan- makes sure that everyone is working on the same project management plan, on the same content and with the same product requirements.

The project management plan helps to solve the following tasks:

1. determining the direction for design work
2. fixing the starting conditions and settings that became the basis of the plan
3. tracking selection results when there are different options
4. establishing communication between project participants
5. definition of criteria by which the management, the project manager and the participants themselves will be able to control and analyze the project.

Despite the huge number of methods and proposed structures of project management plans, one thing remains common: the importance of following the project participants according to the current, approved version of the plan.

Companies critics

Successful cases are a must have for any project management method, which determine its future fate. Consider the most famous by the method of critical chain.

Tonebetsu River Bank Flood Protection Project, Sunagogumi (Japan)

Initially, the project was planned to be completed no earlier than mid-autumn, but using CCPM, it was completed two months earlier - in the first half of August. Thanks to this, Tonebetsu met the typhoon season fully armed. And not just because of the fortified shores: another benefit of using the critical chain method has been to keep local communities and governments informed about progress.

The company inspired the government to promote a human-centric approach to the concept of project management. In 2007, this initiative was launched along with Public Works Reform, which in turn became a public initiative that received national support in 2009.

Delivery of refrigerators and air conditioners, Danfoss

is an international company selling refrigerators and air conditioners in more than 100 countries. Like any growing company, Danfoss faced the classic "management" problems: unproductive multitasking, lack of understanding of the status of projects and their priority. All this has led to long and untenable delivery times for goods. Customer loyalty was rapidly declining, and the company had to make a decision.

The choice turned out to be correct. For 2 years - from the beginning of 2015 to the end of 2016 - Danfoss managed to ensure the delivery of goods on time in 91% of cases. In 2016, the company received only one complaint from a buyer about delivery problems. In working with a new Danfoss methodology, they used project management from Exepron.

Taking projects to a new high level, Radianz

Having created a company - a network of financial services - in 2000, the management immediately encountered a dysfunctional team. Some specialists were guided by the theory of risks, others were focused on the pure sale of the product. Radianz projects involved a high level of uncertainty and complexity, so in order to succeed, it was necessary to find the ideal project management methodology for such conditions.

Mark Steven, director of business planning at Radianz, identified the following tasks:

1. clear visualization of reports on the status of all projects of the company;
2. the ability to plan the use of key resources in various projects;
3. the ability to track the relationship between the effectiveness of the project and the reasons for its success, in order to have an idea of ​​​​futher ways of development and improvement.

To begin with, Mark selected and paid for the training of specialists in the Critical Chain methodology, who later developed a program for introducing the MCC into the company over three stages - from March 2001 to September 2002.

At the first stage, the method was used in two pilot projects, at the second, six more projects were added, and by the fall of 2002, the critical chain method was used in the simultaneous launch of 35 projects.

As a result:

• project efficiency increased by 50%;
• there was a clear visual reporting of the company's activities and individual projects;
• it became possible to trace the relationship between the success and failures of the project and their causes;
• the formation of various kinds of statistics that helped improve the performance of the company.

As of 2016, Radianz has more than 900 employees and an annual income of $250 million.

Applications and Extensions

Software that runs on the critical chain algorithm greatly facilitates the work of project managers and task executors within projects.

Before using applications or extensions, it will be useful to learn how to build a critical chain the old fashioned way - manually. Firstly, you will better understand how to use different functions of specialized software and what it will give to build a circuit, and, secondly, you will be able to figure out where the unexpected results of using programs come from.

Ukrainian cloud service for project management and collaboration of teams along the critical chain. Very convenient for digital and design agencies.

It for CCPM has:

• control of loading tasks of each team member (filter by people), avoids downtime and overload of colleagues
• building chronological links between tasks through a Gantt chart
• setting deadlines taking into account security buffers
• task priorities
• convenient calculation of the resources spent on the task: time, money, employees.

Using the Edrow Max program, you can create diagrams not only using the critical chain method, but also the critical path - with drawing from scratch or using built-in templates.

Verdict

Each of the projects is characterized by certain parameters: purpose, term, resources, degree of novelty. But the main task is proper planning: setting goals, determining resources, both human and material, organizing tasks for the project.

The critical chain method was created to manage large projects, the number of performers and the format of which do not guarantee 100% timely completion of the project. By prioritizing tasks, allocating resources, and adding time buffers, CCPM can significantly reduce the overall time and resource costs of a project.

What is a system of restrictions?

(Theory of Constraints, TOC) is one of the most popular concepts in the management of organizations, developed by Dr. Eliyahu Goldratt in the 1980s. Its main methodological meaning is the search and management of the key limiter of the organization system (commercial or non-commercial). It is this limiter as a whole that determines the effectiveness of the organization.

When we increase the impact on a small number of factors in the system, we achieve the greatest effect compared to if we acted on most of the problem areas at once. TOC - the area of ​​management associated with the constant generation of profits by accelerating the most correlated processes. True, it must be remembered that acceleration cannot grow constantly. Therefore, the main point of the theory of constraints is to identify the constraints within the system that are necessary to keep product quality stable. high level in order to increase profits. The TOC methodology allows the use of certain logical tools, which ultimately reveal the limitations and the managerial contradictions behind them. An important aspect is the simplicity and practicality of implementing solutions using the TOC method. The focus on the implementation of specific business tasks is achieved in 2-3 months. Orientation to mutually beneficial cooperation increases incentives for employees.

Typology of restrictions

TOC is widely used in management, design and production organization.

A constraint is not only an indicator that blocks the system's desire for growth, but also something that, with effective control, will "raise" the system to a new level. The difference between the current and desired state of the system motivates the managers of the organization to look for growth opportunities through the search for restrictions. Capacity, market size (orders), lead time are examples of existing types of constraints.

Restriction types:

Power limit- underutilization of the resource required by the system to create an additional product per unit of time.

Market volume limitation- underutilization of market expectations, which can be used to increase the growth of orders.

Time limit- underutilization of the system's response time to the needs of the market, which ultimately leads to the inability to fulfill obligations to customers, as well as to increase business capacity.

Step-by-step implementation of system management through constraints

The basic steps for managing the system through constraints are quite clear and practical:

Step 1. Search for system limitations.

Step 2 Making decisions about how to maximize the use of system constraints.

Step 3 Subordination of "unlimited" elements of the system to the decisions made.

These steps allow you to control the system and increase its predictability and reliability. Applying these three steps is already on initial stage implementation of TOC can eliminate a significant amount of waste in work.

It is important that the system is in a stable state, which allows you to focus R&D for further growth and profit maximization. For this, the following steps should be used:

Step 4 Expanding the limits of the system by "relieving the stress" that these limits cause. This is achieved through growth production capacity(if it is limited), acquiring additional orders (if the market is limited) and reducing the time spent on order fulfillment.

Step 5 When removing restrictions, you need to return to step 1 and look for restrictions further. It is important that after the first four steps there is no inertial state of calm.

Going from constraint to constraint can lead to organizational instability. Requiring subjugation of all elements of the system, step 3 builds the behavior of the entire system in such a way as to support plans and decisions to the maximum. It is within the framework of this step that the rules and procedures of behavior are formulated, as well as the mechanisms of daily management.

However, changes in the restriction level will affect these mechanisms, rules and procedures. Therefore, it is recommended to identify the strategic limitation and in a certain way to improve the operation of the entire system. This will enable management to focus on the same constraint to ensure that results are achieved.

conclusions

Thus, the theory of constraints is a collection management decisions organization of a product promotion system, project management, management and control over departments, as well as the generation of new strategic decisions.

This methodology equips the organization with the tools to address the four key questions needed for growth:

• What needs to be changed? - Identification of the key problem.
• What to change? - Development of simple practical solutions.
• How to ensure reform? - Cooperation with specialists necessary for the implementation of solutions.
• What creates a continuous improvement process? - Implementation of mechanisms to find those areas that are most in need of improvement.

More articles on this topic can be found in portal libraries.

Over the years systems approach systems improvement deals with three main issues: the problem, the solution, and the implementation of the solution. Theory of Constraints (TOC) provides practical solutions for improving systems in key areas of control. One such area is project management. This article aims to improve the project manager's ability to manage projects in a complex and stressful environment.

The success of synchronized management of an environment where many projects are being implemented simultaneously depends on two global factors: the availability of good professional project managers and the project management method used.

In this article, we want to consider a solution for managing projects according to the method " Critical Chain» ( English Critical Chain Project Management, CCPM). The name "Critical Chain" was chosen to emphasize the difference between the approach CBT away from the traditional Critical Path method. Solution CBT focuses on completing the entire project on time. It is holistic, because it considers the project as a whole, and not each individual task in isolation. It makes sense because we can provide a conceptual framework for the solution using Thinking Processes. TOC. It is mutually beneficial because it takes into account and supports the important needs of key stakeholders.

Projects as a kind of activity are more than a thousand years old. Some of them have resulted in majestic structures that are rightfully considered wonders of the world. However, it was only in the second half of the twentieth century that the importance of project management became so obvious. Demands regarding the time and money invested in projects have become dominant. It turned project management into a profession. The official "start" is the development and use of the diagram for the construction of the Nautilus, the first nuclear submarine in the early 1950s. It was imperative that this critical project be completed within a certain time frame. For planning and management method PERT used the concept English, CPM, Critical Path Method). It subsequently became the predominant approach to project management. It is amazing that the basic principles of project management are still the same as they were 60 years ago, despite the fact that the vast majority of projects fail to complete on time, within budget and original specifications.

USMC - Heavy Equipment Maintenance Base - Albany, GA, USA

Implementation in 2001 of TOC solutions for project management "Critical Chain" and production management "Drum-Buffer-Rope".

Implementation goals:

• Increase the passage (Throughput);
• Reduce costs;
• Reduce the volume of work in progress (WIP);
• Reduce the cycle of repair work;
• Follow the work schedule in 90+% of cases.

Implementation results presented by the base management in the official presentation:

Figure 13. The results of the implementation of TOC solutions based on the maintenance of heavy equipment of the US Marine Corps.

Oded Cowen, International Director of Goldratt Schools,

Elena Fedurko, Regional Director of Goldratt Schools for Russia and Russian-speaking regions

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