Using the Theory of Constraints in Project Management. Theory of Constraints for managing IT projects using the Critical Chain method. Buy a manual cultivator tornado in obi

05.02.2021

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

An 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 was carried out. The prerequisites for the formation of TOC have been identified. The fundamental reasons (within the framework of the general philosophy of TOS) leading to failure to meet construction project deadlines, exceeding their original budgets and changes in content are analyzed. It has been established that such a factor is Murphy's laws, which are amplified by multitasking, a defect in the control mechanism, student syndrome and Parkinson's law. Conducted comparative analysis the critical path method and the critical chain method proposed by E. Goldratt according to 10 basic principles. Using a practical example, the results of scheduling using these two methods are compared. It was revealed that the critical chain method makes it possible to design construction schedules 16% more efficiently compared to the critical path method.

systems constraint theory

critical path method

critical chain method

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

2. Goldratt E.M., Cox D. Goal: The process of continuous improvement: trans. from English E. Fedurko. – Minsk: Potpourri, 2014. – 400 p.

3. Detmer U. Goldratt’s Theory of Constraints: A Systematic Approach to Continuous Improvement: trans. from English U. Salamatova; 2nd ed. – M.: Alpina Business Books, 2008. –444 p.

4. Leach L. On time and within budget: Project management using the critical chain method: trans. from English U. Salamatova; 2nd ed. – M.: ALPINA PUBLISHER, 2014. – 352 p.

5. Rechkalov V. Project management using the Critical Chain method [Electronic resource] // TOCPEOPLE: [site].. URL: http://www.tocpeople.com/2012/10/kriticheskaya-cep/ (access date 07/02/2014 ).

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 was formulated and substantiated by the Israeli scientist Eliyahu Moshe Goldratt in the 80s of the last century. 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 most famous are Lawrence Leach and William Detmer.

Purpose this study is to establish the features of the application of TOS and the critical chain method that follows 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 TOC were first outlined in E. Goldratt’s book “The Goal: The Process of Continuous Improvement,” which was published in 1984. For the field of construction project management and scheduling, the following statements are interesting:

“A system of local optima is not an optimal system at all.” Here E. Goldratt focuses on the fallacy of the traditional approach to understanding system performance, 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;

“Bottlenecks 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 limitation. Therefore, to increase operational efficiency, it is enough to increase the productivity of one link, which will automatically reduce the level of tied capital, as well as operating expenses, by speeding up the passage through the chain of events.

In the same book (“Goal: a process of continuous improvement”), E. Goldratt formulates a sequence of steps to optimize and balance the operation of the system:

Step 1. Find system limitations;

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

Step 3. Coordinate all other actions with this decision;

Step 4. Increase the bandwidth limit;

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

The 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 missed deadlines for project delivery, exceeding the budget and cutting content, and, consequently, reducing 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" (everything that can go wrong will definitely go wrong).

In practice, people always try to take into account this uncertainty by laying down 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 planned profitability indicators, only 1/3 of projects are completed.

The intensification of the effect of Murphy's laws to the point of impossibility of eliminating their consequences occurs due to:

1. Loss of focus of performers due to simultaneous execution and control of several tasks. Multitasking leads to increased work duration due to “jumping” from one process to another. L. Leach gives an example when a performer sequentially works on three tasks during the day, the duration of each of which, subject to continuity, is one week. With the 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 for returning 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 influence of multitasking on the duration of an individual operation within a project

2. Defect in the applied control mechanism that measures the progress of the project. A traditional project progress report typically reflects the following pattern: the first 90% of the work takes up 10% of the time, and the last 10% takes up the remaining 90% of the time. In this situation, timely detection of project areas where Murphy’s law has manifested itself and where corrective measures 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 begin 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. Actions of Parkinson's law: “work expands to fill all the time remaining before its completion.” E. Goldratt notes: “With successive elements, deviations over time are not averaged. Late arrivals accumulate, while time gains do not accumulate.” A performer who completes a task before the designated deadline never announces this, but takes actions to improve the work performed and deliver the results according to the plan. The delays that accumulate from link to link manifest themselves differently. Consequence: the project completion date is pushed back by the sum of these delays.

These factors lead to the complete consumption of the provided safety net, no matter how large it may be, long before the project completion date.

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

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

The critical path is based on time constraints predetermined solely by the technological connections of tasks. At the same time, the dependence of the elements from the point of view of their performer is not taken into account. If a 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 within a project are not technologically related, they may be dependent on a single resource. The connections of elements from the point of view of both technology and the performing 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 uncertainty is taken into account within each task, and in the critical chain it is placed separately at the end of the project (Fig. 2). It should be noted that if the project has no restrictions on resources (performers), then the critical path and the critical chain coincide.

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

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

Table 1

Comparison of critical path and critical chain methods

Name of comparison indicator	Critical path method	Critical chain method
Definition	The critical path is the longest sequence of dependent project elements that have no slack	Critical chain is the longest sequence of dependent elements of a project, consisting of segments that have no reserve time, taking into account restrictions on the use of resources
Static constraint	The critical path may change during 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 defines the start and end dates of the project.	The critical chain only records the completion date of the project (after adding the project buffer). The start of a project can also be determined by a non-critical task
Defining task durations	The duration of tasks is estimated by calculation or expert method, taking into account “safety net” based on previous negative experience	The duration of tasks, determined by 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 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	The start and end dates of individual tasks are not important. It is necessary to carefully monitor the state of protective buffers and the activity of their consumption.
Assessing Project Progress	To assess the progress of the project for a certain date, a fixed date for the completion of a particular stage of the project (milestone) is used	All completion dates for one or another project stage (milestone) are floating. To assess progress, it is enough to determine whether the stage is in the completion stage, as well as analyze the consumption of the protective buffer to indicate the probability of completion of the stage by a certain date
Time reserves 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 must 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 delays that occur 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 distribution due to the lack of a “real difference” exceeding the degree of uncertainty in the project, which is extinguished in the buffers laid down.

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 for eliminating resource conflicts, does not exceed 4%, which confirms E. Goldratt’s opinion about the ineffectiveness of optimization and allows the use of any form of resource leveling when planning.

The comparison results are shown in table. 2.

table 2

Comparison of graphs generated using the critical path and critical chain methods

Name	Number of days
Critical path method
Before resource leveling
After alignment (according to two options - using the built-in MS Project function)
Critical chain method
Alignment using the built-in MS Project function (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 using the critical path method

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

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

Performance of any system, incl. and construction and investment project, is determined by the productivity of the weakest link, which acts as a limitation; in a construction project, such a constraint is the critical path;

Due to the presence of limitations, as well as the uncertainty inherent in the functioning of the system, the vast majority of projects experience missed deadlines, cost overruns, and scope cuts;

The critical path method takes into account the time limitation of the project, but does not take into account restrictions on resources (performers), therefore, in construction projects, the use of the critical chain method is more justified (a 16% improvement in the schedule was recorded);

The effectiveness of optimization algorithms and methods is questionable; their use is a labor-intensive process that does not significantly improve scheduling results (a simple example revealed differences between schedule options that did not exceed 4%).

Reviewers:

Bolotin S.A., Doctor of Technical Sciences, Professor, Federal State Budgetary Educational Institution of Higher Professional Education "SPbGASU", St. Petersburg.

Vatin N.I., Doctor of Technical Sciences, Professor, Federal State Educational Institution of Higher Professional Education "SPbSPU", St. Petersburg.

Bibliographic link

Kotovskaya M.A. FEATURES OF THE THEORY OF CONSTRAINTS OF GOLDRATT SYSTEMS AND THE CRITICAL CHAIN METHOD IN THE FIELD OF SCHEDULE PLANNING OF CONSTRUCTION PROJECTS // Modern problems of science and education. – 2014. – No. 4.;
URL: http://science-education.ru/ru/article/view?id=14374 (access date: 02/01/2020). We bring to your attention magazines published by the publishing house "Academy of Natural Sciences"

Whether you work in services, industry, IT, design or marketing, project management is an essential part of your business. Any company is constantly undergoing changes. And in order to cope with the problems that arise 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 completion of the project leads to the opportunity to earn new money. Therefore, the most important question becomes: can we meet the deadline and the allocated budget? The traditional approach to project management looks like this: a project is broken down into individual tasks, which are assigned calendar start and end dates. A well-written plan is assumed to be easy to implement. But how can all unforeseen circumstances be taken into account in this case? Is it possible to effectively initiate, plan and control projects based on intuition alone? How to reduce risks in this case? At the same time, it is known that even well-planned projects during their execution run out of 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 occurring. 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; a suitable 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 you get timely information about those tasks that are currently leading to delays and jeopardizing the budget. At this seminar you will receive a tool that will allow you to set priorities, identify current project tasks, and accurately allocate resources.

The target audience: executives managing a multitasking environment, project managers, marketers, designers, IT specialists.

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

In this seminar you:

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

Seminar program

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

Undesirable phenomena in projects: missed deadlines, repeated postponements of completion dates, budget exceedings, rush jobs and overtime, cuts in functionality and specifications, constant lack of resources, competition for them.
- Problems that interfere with project management.
- Features of project management for seminar participants.
- The main characteristics of the project management environment: uncertainty, multitasking, local performance indicators.
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.
Introduction to TOS. Principles and premises.
Root conflict of the project environment.
Main misconceptions in project management:
- a game that demonstrates the impact of multitasking;
- discussion of student syndrome and the Parkinson's effect.
Competitive advantage in project environment(reliability of deadlines, quality assurance and budget adherence).
The critical chain concept (CCPM) and its difference from the critical path concept.
Agile philosophy. Scrum concept for project management.

2-3rd day. Project management using the critical chain method

Management setting and the introduction of new performance indicators that allow you to see the dynamics of income from projects.
Reduce multitasking:
- freezing some ongoing projects;
- accelerating the implementation of remaining projects;
- defrosting projects as the previous ones are completed, "virtual drum";
- launch of new projects.
Tool Kit (complete preparation of the project for launch):
- preparing projects in accordance with priorities;
- determining the scope of work for project preparation;
- eliminating the risk of losing clients due to late launch of projects.
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;
- echeloning of the project portfolio.
Project execution management:
- daily reporting on task completion, communication issues;
- ensuring that tasks are completed and prepared in accordance with established priorities;
- timely adoption of corrective measures by top management;
- regulation of execution speed at the point of project integration.
Elimination of project delays caused by clients.
Placing orders with subcontractors:
- control of work performance;
- using effective incentives for on-time performance on the part of the contractor.
Selling the reliability of completing projects on time.
Workload control: regardless of sales growth, the company always meets deadlines.
Continuous Improvement Process:
- report on the reasons for delays;
- analysis of the causes of delays;
- initiating projects to improve performance.
Power Expansion:
- identification of resources responsible for delays in projects;
- ensuring timely availability of the necessary labor resources.
Implementation competitive advantage"early delivery":
- formation of a “bonus market”;
- development of a bonus offer;
- sale of "early delivery";
- quick completion of the project.
Project management software for TOC and Scrum.
Organization of work in a project using the Scrum method:
- planning and prioritization of work;
- roles of product owner and scrum master;
- holding scrum meetings;
- conducting a retrospective.
Combined use of CCPM and Scrum techniques.
Examples of the application of the critical chain method and Scrum at enterprises in various industries.

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

We have already looked at different project management methodologies in previous reviews. You can check out , , and .

Today we will talk about:

how to estimate and predict project timelines from scratch in CCPM?
What rules do you need to know to calculate time correctly?
Why is the critical chain method the choice of hundreds of successful companies?
How to introduce the critical chain method (MCM) in your company?
How can I implement CCPM using the Worksection service?

Origin of the methodology

The concept of “critical chain method” was first introduced in the book. Eliyahu's predecessor books presented individual ideas and techniques that later merged into CCPM, from the Drum-Buffer-Rope (DBR) method 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 organizational management methodology created by Eliyahu Goldratt. The basis of TOC is the search and management of 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 limitations of the system, subordinating production to the maximum effective use restrictions. It is built on the use of a work schedule for restrictions (drum), in which a protective buffer is prescribed that protects against idleness (buffer), and on organizing 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. The 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 well-forgotten old, CCPM turned out to be similar to both Goldratt’s TOC and PERT method. The latter was developed to calculate the expected duration of a project or the time to achieve objectives at certain stages of the project, 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 and then use them when constructing a diagram.

All previous methods developed before the beginning of the second half of the 20th century are morally outdated. The critical chain method became the first effective method project management after the development of PERT, and yet... 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 the methodology in business project management. Every year dozens of books on project management appear on the shelves, which in one way or another use the critical chain method (we recommend), and created by the founder of the method, Goldratt, the British company Goldratt offers services for the implementation of CCPM in the project management of companies.

Estimating project timelines from scratch using CCPM

When starting to work on the critical chain (CC) of a 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 in which a task will be completed, they will, at best, indicate the time with a reserve, and at worst, they will assure that the task will be completed quickly and put the entire project at risk.

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

Estimation of deadlines should be carried out based on 100% artist load. This, firstly, will keep all performers on their toes, preventing downtime, and, secondly, will significantly reduce the overall duration of the project.
part of the assessment time should be allocated to buffers— this part can be calculated using a simple scheme: the total estimated time is divided in half, and the second half becomes a buffer;
the difference between the average and probable time estimates must be significant - use a factor of 2x or more(more on this later). This will help avoid a formal distinction between different types timing and will be useful when using the PERT method.

It is convenient to calculate the time it takes to complete individual tasks in a project and its completion using the PERT method. But determining deadlines based on 3 time values (best, likely and worst) does not include the likelihood of failures and delays. The most important tool to combat them is the project buffer, which is placed between the completion date of the last task and the completion date of the project. Thus, the length of the critical chain, and therefore the project duration, 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’s worth deciding in advance whether task deadlines will be indicated. with buffer or related tasks will have start dates shifted.

In addition to the project buffer, it is important to consider the feed buffer (path merge buffer)- time reserve, which is located between the stage of operation of the non-critical chain and the stage of work within 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 diagram

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:

optimistic (best);
expected (probable);
pessimistic (worst).

The longer the total duration of the project, the higher the cost of error: the number of variables increases, statistical errors in time estimation grow, and the risk of changes to key elements of the plan appears. To combat these problems, you can look to the surfer. He constantly balances to stay on top of the wave on the board for as long as possible. There is no single correct body position!

This is what inspired the creation of “travelling wave planning”. Thus, Bans Landsdorp's Mars One project assumed the duration of the Mars colonization project to be 22 years - from 2011 to 2033. Each stage took 1-2 years, and was described on the official website of the project. But the lack of experience in solving the assigned tasks and the uniqueness of the project led to the fact that the expected deadlines shifted. The expected duration of the project has increased to 24 years!

Why do we even need three values? 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 time of the operation (project);
tO — optimistic (best) time;
tM—expected (probable) time;
tP — pessimistic (worst) time.

As with any calculations, errors are possible here. The PERT method, by its specificity, underestimates the expected duration of a project task.
This means that the more tasks there are, the more errors you may encounter.

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

This is what a PERT chart looks like

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

Arrows- determine the direction from one task to another, and indicate events that must occur;
Numbers— 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 chart, which determines the time within which all project tasks are completed.

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

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

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

Advantages and disadvantages of the methodology

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

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

Benefits of CCPM:

leveled resource load over time - unlike the critical path method, you are not constrained by a strict sequence of tasks or strict planning.
one task is completed in one unit of time - this can be considered both a plus (there is no danger of layering tasks) and a minus, because increased demands are placed on the performer for the ability to quickly switch between tasks and task chains.
it is easy to detect emerging delays and threats of missing project completion dates - thanks to buffers (project, resource and time buffers and a feeding buffer), the project manager is able to “protect” the project completion date from task variations.
focusing resources on critical tasks - eliminates competition for resources within the project.
eliminates such project diseases as “student syndrome”, the use of multitasking, and the effect 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 International Exhibition Center, which 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:

increased project implementation time - this occurs due to time buffers, since when using the critical chain method, the key is the completion date of the entire project, and not the completion date of an individual task. In most cases, the longer a project takes, the higher its cost.
increased requirements for the qualifications 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. You can't do without it either.
the cumbersomeness of the critical chain method in its “dry” form - when creating a CCPM plan, you have to take into account a dozen factors: tasks, deadlines, buffers and much more. Even if the project manager understands these complexities, how can you show management how it really works? After all, the original plan will change when further development project. And the main goal of the project is not the implementation of the plan (even if it is worked out in detail), but the effective achievement of the stated goals.
the need to form separate teams for each project stems from the inability to use one resource simultaneously in several different projects. In this regard, Oded Cowan, an international TOC expert, noted that the MCC is more suitable for large projects and enterprises, in particular in the areas of installation of telecommunication networks, repair and refurbishment of aircraft, and development of products for new generation wireless technologies.

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

“Student syndrome” - the more time allocated to complete a task (including backup), the later a 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 dealt with by limiting the time to complete the task.

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

Parkinson's Law - The amount of work tends to increase to fill the time allotted for its completion.

Murphy's Law - "if trouble can happen, it will happen." The subconscious also knows about Murphy’s law, so project participants strive to insure themselves by laying down a reserve of time and extending the deadline for completing the task several times.

An alternative view: differences between the critical chain method (CCPM) and the critical path method (CPM)

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

the critical path in CPM has an “idealized” character; in CCPM the path is built taking into account resource limitations.
the main tasks of CPM are project planning, determining the highest priority tasks; The main goal of the critical chain method is to complete the project as quickly as possible, taking into account resource constraints.
The critical path method is based on forecasting project deadlines, while CCPM is based on the initial uncertainty of the duration of the work.
The critical path method is more suitable for determining product release dates, while CCPM is more suitable for projects in which the deadline is already known.
The critical path method is based on a rigid sequence of tasks, while the critical chain method is based on flexible planning.

CCPM has two fixed deadlines - 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 the sequence of tasks in a project. 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 the resources for their implementation. In this respect, CCPM is similar to CPM (which is why they are so often confused): the longest path of the chain is critical .

Lawrence Leach, in On Time and on Budget: Critical Chain Project Management, warns against a common mistake. Often managers use the initially constructed 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 circuit, taking into account resource limitations.

Virtual critical chain
its properties are similar to a regular chain.
It is important to remain strong under tension.
The strength of each chain is determined
the 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 he 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”, thanks to which the project in absentia received high marks in the press and the titles of “Best Original Game” and "Best game from an independent developer" even before release. One of the most important links was the creation of a design document and, as shown negative reviews after the product is released to the market, the weakest.

Boring gameplay, lack of original ideas and the harmonious game concept buried hope for success. And even a powerful marketing campaign, ordering advertising in the largest specialized publications and good graphic design did not save us from complete failure in the market. Thus the weak link burst - the design document ( detailed description the computer game being developed, the plot and essence of the project), the basis of the foundations of the game project - and the whole chain fell apart, losing its meaning.

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

Comes into effect theory of constraints (TOC), which reinforces the critical chain method. One of the rules of TOC is that a project can only do as much work as allows you to make the weakest link in the chain. In simple terms, work must be started in accordance with the strength of the weakest link.

In the case of No Man’s Sky, having identified the design as the weakest element, the developers had two options:

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

No one will dispute the uniqueness of each project: goals, deadlines, resources, 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 summary of practical steps for using the MCC in individual project planning. It will be useful to you even if you have already encountered CCPM while working on projects. If 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:

Explain to the team who will be working on the project the importance of protecting management's estimates of task durations and resources. Unfortunately, chaotic and rapid completion of assigned tasks may look impressive, but not effectively, 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 budgets, but he will set this only after coordination and approval with the entire team.
Eliminate contention for resources by load balancing. Thanks to this, the need to switch resources between tasks will also disappear.
Notice the unevenness of the load in You can use the People tab, where you can see how many tasks each specific performer has.
Plan tasks that do not depend from any other tasks, starting from the end date of the project to the beginning!
The built-in Gantt Chart allows you to indicate which tasks are related and which are independent of others.
To permanently solve the problem of resource unavailability, add resource buffers to the critical chain.
You can use Labels to indicate which resources are needed for a task and control the load in the task list.
Insert a design buffer at the end of the project to accumulate slack 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 a task “Final/Project Delivery” and assign its Start Date to the day after all tasks plus reserve time. The same date should be announced to customers.
Calculate and arrange supply buffers for all paths on which critical circuits depend.
This should be done before setting Start and End Dates for tasks.
Develop a working scheme for tracking the performance of performers on tasks. They must work as quickly as possible and not delay the delivery of the results of the work upon 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 critical chain project plan 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 competition Eurovision in Ukraine, what do you need to do according to CCPM?

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

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

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

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

3. Indicate the initial resources - performers, finances, material and technical base. Most companies have a base of specialists with whom they maintain connections.

Therefore, the search and selection of specialists who will be involved in the technical support of the Arena will first take place according to the already existing list. Before drawing up a request, you need to update your 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 may arise 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 Eurovision volunteer coordinators in your team have 900 volunteers under their supervision. Moreover, each of them often works in two sectors. The ill-considered use of such a powerful human resource can lead to confusion and ineffectiveness. Therefore, it is more logical to set up a shift schedule, according to which some volunteers will always be free and can be involved in solving “emergency” or minor current tasks, such as the formation of packages with souvenirs 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 schema.

You can randomly arrange instructions for Eurovision volunteers: first aid, evacuation, conversation course in English etc. But when selecting, among the conditions you already set “knowledge of the English language 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 take a break from Eurovision. The Lockheed company, which specializes in creating aircraft for 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 has been set quite clearly - February 19, 2017. Having worked through the plan using the critical chain method, you realize that 1 year 3 months is enough for you to launch an experimental prototype.

Taking into account possible technological innovations, bureaucratic problems with registering a 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 all tasks are necessary to achieve the end goal.

Lockheed's policy is to widely publicize its internal workings, 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 an individual critical chain, rather than the entire project. This is a safety net for managers and teams working on projects with clear deadlines.

A clear example of howsaves the project from missing deadlines

Several Lockheed departments are involved in the work on the drone, each of which is responsible for a separate component of the aircraft. To carry out their tasks within the framework of the general critical chain, the rule from clause 6 works - a safety buffer of 50% of the duration of the critical chain for the creation of 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 Habrakhabr, a team of 7 people, plus or minus two employees, is considered optimal. What if there are 30 of them, like in the Lockheed drone project? What if there are more than 1,000, as is the case with the Eurovision preparation project?

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

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

Project management plan using the critical chain method

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

The project management plan includes:

detailed description of the project content— without understanding the specifics, importance of the project, and its goals, it is impossible to draw up a high-quality working plan for managing this project.
work breakdown structure for project execution— to create an unmanned vehicle for aerial photography and video filming, the simplified hierarchy looks like this: first you need to create a concept for the device, then you need to carry out everything necessary calculations and only then build a prototype. If you change the order, the project will never reach its logical end.
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.
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 (the project schedule with aligned resources), they add:

separate subject plans for security, supplies, personnel, etc. IN International standard in ISO 21500:2012 project management, they are also called “subject groups”. In the case of Lockheed creating a drone, the subject procurement plan will include the processes necessary to acquire outsourced specialist services and electronic control systems for the device, 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 a 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 may include sanitary-hygienic and sanitary-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 selected.
change management plan- Ensures everyone is working on the same project management plan, on the same content, and with the same product requirements.

A project management plan helps solve the following problems:

determining the direction for design work
fixation of starting conditions and settings that became the basis of the plan
tracking selection results when there are different options
establishing communication between project participants
defining criteria by which management, the project manager and the participants themselves will be able to monitor and analyze the project.

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

Critical companies

Successful cases are a must have of any project management method, which determine its future fate. Let's consider the most famous ones using the critical chain method.

Project to strengthen the banks of the Tonebetsu River against flooding, 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 prepared. And not only thanks to the fortified banks: another advantage of using the critical chain method was the streamlined communication of progress to the local population and the government.

The company has inspired the government to promote people-centric project management concepts. In 2007, this initiative was launched in conjunction with Public Works Reform, which in turn became a community initiative that gained national support in 2009.

Delivery of refrigeration chambers and air conditioners, Danfoss

is an international company that sells refrigerators and air conditioners in more than 100 countries. Like any growing company, Danfoss was faced with classic “management” problems: unproductive multitasking, lack of understanding of the status of projects and their priorities. All this led to protracted and uncritical delivery times for goods. Consumer loyalty was plummeting, and the company needed 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 delivery of goods on time in 91% of cases. In 2016, the company received only one complaint from a customer about delivery problems. When working with a new methodology, Danfoss used project management from Exepron.

Taking projects to a new high level, Radianz

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

Mark Stephen, Director of Business Planning at Radianz, identified the following objectives:

clear visualization of reports on the status of all company projects;
the ability to plan the use of key resources in various projects;
the ability to track the connection between the effectiveness of a project and the reasons for its success in order to have an idea of further ways of development and improvement.

To begin with, Mark selected and paid for the training of specialists in the Critical Chain methodology, who subsequently developed a program for introducing 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%;
clear visual reporting of the company’s activities and individual projects appeared;
it became possible to trace the connection between the success and failure of the project and their causes;
generation of various kinds of statistics that helped improve the company’s performance.

As of 2016, Radianz had more than 900 employees, and annual income amounted to $250 million.

Applications and extensions

Software running on the critical chain algorithm greatly facilitates the work of project managers and task performers within projects.

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

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

It contains for CCPM:

monitoring the workload of each team member with tasks (filter by people), avoiding downtime and overloading colleagues
building chronological connections between tasks using a Gantt chart
setting deadlines taking into account security buffers
task priorities
convenient calculation of resources spent on a 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: goal, deadline, resources, degree of novelty. But the main task is proper planning: setting goals, identifying resources, both human and material, organizing tasks for the project.

The critical chain method was created for managing large projects, the number of performers and the format of which does not allow guaranteeing 100% timely completion of the project. By prioritizing tasks, distributing resources and adding time buffers, CCPM can significantly reduce the final time and resource costs of project implementation.

What is a restriction system?

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

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

Typology of restrictions

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

A limitation is not only an indicator that blocks the system’s desire to grow, 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 organization's managers to search for growth opportunities through the search for limitations. Capacity, market volume (orders), lead time are examples of existing types of constraints.

Types of restrictions:

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

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

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

Step-by-step implementation of system control through restrictions

The basic steps for controlling a system through constraints are quite clear and practical:

Step 1. Search for system limitations.

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

Step 3. Subordination of “unlimited” elements of the system to accepted decisions.

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

What is important is that the system is in a stable state, which allows scientific development to be focused for further growth and profit maximization. For this, the following steps should be used:

Step 4. Expanding the limitations of the system by “releasing the tension” that these limitations cause. This is achieved through growth production capacity(in case it is limited), the acquisition additional orders(if the market volume is limited) and reducing the time spent on order fulfillment.

Step 5. When eliminating restrictions, you need to return to step 1 and continue to look for restrictions. It is important that after the first four steps an inertial state of calm does not set in.

Moving from constraint to constraint can lead to organizational instability. Requiring the submission of all elements of the system, step 3 arranges 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 conduct, as well as the mechanisms of daily management, are formulated.

However, changes in the level of restriction will affect these mechanisms, rules and procedures. Therefore, it is recommended to identify the strategic limitation and organize the operation of the entire system in a certain way. This will make it possible to focus management's attention on the same limitation, which will ensure the achievement of results.

conclusions

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

This methodology equips an organization with management tools that will answer four key questions needed for growth:

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

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

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

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

In this article we want to look at a solution for project management using the “ Critical Chain» ( English Critical Chain Project Management, CCPM). The name "Critical Chain" was chosen to highlight the difference in the approach CBT from the traditional "Critical Path" method. Solution CBT focuses on completing the entire project on time. It is holistic because it looks at the project as a whole, rather than each individual task in isolation. It makes sense because we can provide a conceptual framework for the solution using Thought Processes TOC. It is mutually beneficial because it addresses and supports the important needs of key stakeholders.

Projects as an activity are over thousands of years old. Some of them 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 clear. Requirements regarding time and money invested in projects have become dominant. This has turned project management into a profession. The official “start” was the development and use of the diagram to build the Nautilus, the first nuclear submarine in the early 1950s. It was imperative to complete this critical project within a specific time frame. For planning and management method PERT used the concept ( English, CPM, Critical Path Method). It subsequently became the dominant 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 be completed on time, within budget and within original specifications.

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

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

Implementation goals:

Increase 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.

The implementation results presented by the base management in the official presentation:

Figure 13. Results of implementing 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