國 立 交 通 大 學
工業工程與管理學系
博士論文
應用遊戲與模擬克服 CCPM 導入的兩大障礙與驗證
CCPM 的有效性
Using Games and Simulations to Overcome Two
Obstacles that Block the Introduction of CCPM to PM
Society and Validate its Effectiveness
指導教授：李榮貴 教授
研 究 生：黃佳玲
應用遊戲與模擬克服 CCPM 導入的兩大障礙與驗證
CCPM 的有效性
Using Games and Simulations to Overcome Two Obstacles
that Block the Introduction of CCPM to PM Society and
Validate its Effectiveness
指導教授：李榮貴 教授 Advisor: Dr. Rong-Kwei Li
研 究 生：黃佳玲 Student: Chia-Ling Huang
國 立 交 通 大 學
工業工程與管理學系
博士論文
A Thesis
Submitted to Department of Industrial Engineering and Management
National Chiao Tung University
in partial Fulfillment of the Requirements
for the Degree of Doctor
in
Industrial Engineering and Management
June 2011
Hsinchu, Taiwan, Republic of China
用遊戲與模擬克服 CCPM 導入的兩大障礙與驗證 CCPM 的有效性 學生：黃佳玲 指導教授：李榮貴 教授 國立交通大學工業工程與管理學系（研究所）博士班 摘 要 自 1997 年起，限制理論(TOC)關鍵鏈專案管理(CCPM)方法已獲得了相當可觀的關 注，已有數以百計導入 CCPM 成功的案例，在專案管理環境達成高度可靠的準時達交和 縮短專案完成時間。但是，CCPM 導入專案管理環境仍存在兩大障礙，第一個是實務界 從事專案管理者表示：對於 Goldratt 宣稱專案管理方法只要做一些簡單的改變就能夠顯 著改善專案準時達交和專案完成時間缺乏信心。第二個是學術界的一些學者聲稱：CCPM 並非新知識且對於專案管理知識體系(PMBOK)無實質的貢獻。在本研究中，首先利用專 案管理遊戲克服第一個障礙。接著，排除不良的人類行為後，比較研究 CCPM 和計劃評 核術/要徑法(PERT/CPM)克服第二個障礙。結果顯示：(1) 專案的管理方法是造成專案 準時達交和縮短專案完成時間的根本原因，且改變專案管理方法能夠顯著改善專案準時 達交和專案完成時間。(2) 根據專案平均完成時間，CCPM 未顯著優於 PERT/CPM，但 是根據專案規劃交期的可靠度，CCPM 優於 PERT/CPM，這是由於 CCPM 的規劃方法 改變，因此比 PERT/CPM 規劃方法產生較合理且可靠的專案規劃。 關鍵字：專案管理、關鍵鏈專案管理、限制理論、計劃評核術/要徑法
Using Games and Simulations to Overcome Two Obstacles that Block the Introduction of CCPM to PM Society and Validate its Effectiveness
Student: Chia-Ling Huang Advisor: Dr. Rong-Kwei Li Department of Industrial Engineering and Management
National Chiao Tung University
Abstract
Since 1997, the Critical Chain Project Management method (CCPM) has received considerable attention. Hundreds of successful CCPM cases have achieved highly reliable on-time delivery (OTD) with short project lead-time (PLT) in multi-project environments. However, two obstacles have remained, blocking the introduction of CCPM to project management (PM) society. The first has been addressed by PM practitioners, who have been less than confident that OTD and PLT can be significantly improved by simply changing the way to manage multi-projects. The second is from academia: some scholars have claimed that the ideas of CCPM are not new and are of no substantial contribution to PMBOK. In this study, we first used multi-project management games to overcome the first obstacle. A comparative study of CCPM and PERT/CPM planning methods, excluding bad human behaviors, was then conducted to overcome the second obstacle. Results show that: (1) the ―mode of managing multi-projects‖ was the root cause, and changing the mode of managing multi-project could significantly improve OTD and PLT; (2) in terms of mean project time, CCPM is not significantly better than PERT/CPM. However, in terms of plan reliability, CCPM achieves higher than PERT and CPM. This is due to a CCPM logistical change that generates a more reasonable and reliable project plan than do the PERT/CPM methods.
Key Words: Project Management, Critical Chain Project Management, Theory of Constraints, PERT/CPM
誌謝 除了真摰的由衷感謝，依然是感謝。
黃佳玲 謹識 中華民國一百年六月
Contents Chinese Abstract --- i English Abstract --- ii Acknowledgments --- iii Contents --- iv Table --- v Figure --- vi 1. Introduction--- 1 2. Literature reviews--- 8 2.1 Fundamental of CCPM--- 8 2.2 Review of CCPM literature--- 14
2.3 CCPM Strategy and Tactics tree--- 18
2.4 Successful cases of CCPM--- 30
3. Using games and simulations to overcome first obstacle that block the introduction of CCPM to PM practitioners--- 31
3.1 Design of multi-project management games--- 31
3.2 Analysis of the games and simulation experiment--- 37
3.3 Conclusions--- 44
4. A comparative study of the CCPM excluding bad human behaviors to overcome the second obstacle--- 46
4.1 Project Planning—CCPM vs PERT--- 46
4.2 Project execution—CCPM vs. PERT--- 51
4.3 Conclusion--- 57
5. Conclusion--- 59
References --- 61
Appendixes Appendix A --- 65
Table
Table 1.1 Compare the simulator results --- 6
Table 3.1 Results of three games--- 38
Table 3.2 Five top reasons--- 39
Table 3.3 Reliability of the planned completion day with simulation--- 40
Table 3.4 Data related to project execution in Game 1 and 2--- 41
Table 3.5 Polling questions and answers before and after game--- 44
Table 4.1 Estimated duration of single project--- 49
Table 4.2 Estimated duration of Multi-project--- 51
Table 4.3 Simulation results of single project--- 52
Table 4.4 Simulation results of Multi-project--- 54
Figure
Figure 1.1 (a) CCPM Single Project Plan, (b) Single Project Plan with no logistical
change--- 7
Figure 2.1 The steps of critical chain planning--- 9
Figure 2.2 The steps of projects staggering of CCPM--- 11
Figure 2.3 Visual Buffer management--- 14
Figure 2.4 (Goldratt 2009): A complete structure of S&T tree--- 20
Figure 2.5 (Barnard 2008, 2009): The SDBR S&T tree--- 22
Figure 2.6a (Barnard 2008, 2009): The details of CCPM S&T tree level 1 and 2--- 24
Figure 2.6b (Barnard 2008, 2009): The details of CCPM S&T tree level 2and 3--- 25
Figure 2.6c (Barnard 2008, 2009): The details of CCPM S&T tree level 2and 3--- 26
Figure 2.6d (Barnard 2008, 2009): The details of CCPM S&T tree level 2and 3--- 27
Figure 2.6e (Barnard 2008, 2009): The details of CCPM S&T tree level 2and 3--- 28
Figure 2.7 (Barnard 2008, 2009): Step 2.1 of CCPM S&T tree--- 29
Figure 3.1 A Multi-Project management game with three similar projects--- 32
Figure 3.2 Layout of the game--- 33
Figure 3.3 Task Card--- 33
Figure 3.4 (a) Theoretical Estimated task time duration, (b) Actual task time duration--- 34
Figure 3.5 Task card (front)--- 35
Figure 3.6 Multi-project plan--- 37
Figure 4.1 Multi-Project environment involved three similar single project network- 46 Figure 4.2 Three different task uncertainties, low, medium and high--- 47
Figure 4.3 Single-Project CCPM/PERT with uncertainty medium--- 49
1. Introduction
Since Goldratt first published the Critical Chain book in 1997 (Goldratt 1997a), proposing the Critical Chain Project Management method (CCPM), the CCPM has received a lot of attention in the project management literature and has recently emerged as one of the most popular methods of project management in a multi-project environment. In the past 15 years, many project management practitioners and researchers have written books (Newbord 1998, 2008, Leach 2004 and Yuji 2010) and conducted research to enhance and spread CCPM knowledge (Steyn 2000, 2002, Rand 2000, Herrolen and Leus 2001, 2002, Elmaghraby, Herroelen and Leus 2003, Cohen, Mandelbaum and Shtub 2004, Ashtiani 2007, Jacob and Mendenhall 2008, Long and Ohsato 2007, 2008, Liu 2008, Rezaie 2009 and Cui 2010), developed software systems (Realization 2011, Prochain 2011) to support CCPM implementation, and created implementation strategy and tactics to guide practitioners in how to implement CCPM (Goldratt 2009).
CCPM method achieves highly reliable on-time delivery (OTD) and short project lead-time (PLT) in a multi-project environment mainly because it focuses on changing the way to manage multi-projects, efficiently using the safety time embedded in tasks through two changes: logistical change (planning aggressive task times with 50 % buffers, staggering the release of projects, and determining priorities with buffer management) and changing bad human behaviors (no bad multi-tasking, no exhibition of student syndrome, and no practicing of Parkinson‘s Law). Although related literature has reported hundreds of successful cases achieving highly reliable OTD with short PLT in a multi-project environment (Realization 2011, Goldratt Marketing Group 2011), the introduction of CCPM to project management society still encounters two obstacles. The first is from project management practitioners, who have been less than confident that OTD and PLT, in a multi-project environment, can be significantly improved by simply changing the way to manage multi-projects. The second is from academia: some scholars have criticized the approach as offering nothing new.
Concerning the first obstacle, our interviews with local managers revealed that few agreed that the mode of managing multi-projects is the root cause of poor OTD and long PLT. The interviews were conducted in three-hour public workshops1 attended by more than three hundred people. The majority of the participants were project managers, resources managers, and engineers. The polling question was: why is it difficult to achieve high OTD in
1 During the year of 2009, four workshops (January, 17th, March 14th, May 9th and June 13th) were conducted on
multi-project management? We asked them to not just write the reasons they believe in, but also what they think others believe in. Ninety percent of their responses can be summarized as excessive task time variability (or uncertainty). Such as resources and the time available for projects are often inadequate, and tough situation becomes dire when exacerbated by severe competition in the market place. Clients and management are often slow to make decisions, delivery from suppliers is sometimes delayed, and information is not always shared in a timely manner. Moreover, project scope/specifications change and often creep. Even when problems arise, support is not necessarily forthcoming (from management or from other project stakeholders) without delay. In spite of these difficulties, project members work very hard, with a strong sense of responsibility and urgency, and are even willing to work around clock to comply with all kinds of expectations from stakeholders. Looking carefully into these uncertainty problems, it has become obvious that they do not originate within the project, but rather exist outside the project. Therefore, project members often believe that they can do little to overcome these problems even with CCPM.
In light of the above results, it is not surprising that reducing uncertainty thus has become the focus of improvement efforts, with programs such as PDM and Six Sigma becoming the norm. Unfortunately, the second polling question (if they have adopted PDM and Six Sigma programs, was OTD improved significantly?) in three-hour public workshops1 found that for eighty percents of participants, OTD remained a major issue. Only twenty percents of the participants indicated that their OTD improved, and only through long-term effort.
Theoretically, it is not difficult to achieve highly reliable OTD in multi-project management. First, an accepted Project Evaluation and Review Technique (PERT) or Critical Path Management (CPM) network and its estimated project lead time (PLT) should be determined for each project. Since uncertainty exists, this estimated PLT should have a sufficient safety time to handle uncertainty; if not, it will be difficult to meet the deadline (Goldratt 1997b). The greater the uncertainty, the bigger the safety embedded in the task‘s time estimates. Second, the starting and ending times of each project should be scheduled according to the required completion date and resource limitations. If the required completion date can be achieved, then the project is confirmed. If the required completion date cannot be met due to capacity loading, the project will be given a new completion date. If the new completion date is accepted, planning is complete. If not, negotiation is initiated or the project
is simply lost. When planning is complete, project execution begins. In most multi-project environments, to better utilize human resources, most employees are not dedicated to a single project, but must multi-task. They are organized in resource groups according to their skills, and each group performs certain types of tasks for several projects. The responsibility of these teams is to turn task time estimates into commitments. In addition to resources managers, project managers are also in charge of the project. Their responsibility is to make sure that the project is completed according to the original commitments. In the multi-project environment, projects are usually managed in a matrix structure. The progress of each project is reported periodically, and task priorities are shuffled according to urgency. Recovery plans for projects falling behind schedule are discussed and executed as necessary.
As stated above, the mode of planning and controlling multiple projects to achieve high OTD is obvious. If excessive uncertainty is the main challenge in OTD, as claimed by the managers interviewed in this study, and improvement programs for reducing uncertainty are also initiated, OTD should be significantly improved. However, the reality is that it is not improved (or improved slowly) (Standish Group 2007).
So what is the true root cause to poor OTD in multi-project management? Although Goldratt claims these problems (originating outside the projects) do not appear to be the root cause of poor OTD and long PLT in multi-project management; rather, the mode of managing multi-projects does. Specifically, four major causes related to the mode of project planning and execution will significantly affect OTD and project lead time, which are: (1) Unrealistic planning (over-promise), meaning that most key resources work across projects in a multi-project management, but poor planning fails to consider resource contentions across projects. This makes the plan unrealistic and leads to missed commitments and long project lead times; (2) A lack of clear working priorities, meaning that engineers will work on the wrong priority project in a multi-project management due to a lack of clear priorities. Working on the wrong priorities causes an interruption in the critical chain, which in turn causes a cascading effect in other tasks and ultimately leads to missed commitments and long project lead times; (3) Bad-multi-tasking, meaning that project managers in multi-project environments will release a project as soon as possible because they fear that projects will not finish on time. Releasing projects too early causes too many projects to be executed simultaneously (resources competition), which means that many resources will suffer from bad-multi-tasking. Extensive bad-multi-tasking drastically increases the lead time of both tasks and projects, which further leads to missed commitments and long project lead times.
Bad-multi-tasking also cause, in the down-stream departments, overloads follows by under loads, which creates a tendency to release more work into the system so that people will always have something to work on, which increases bad-multi-tasking, a vicious cycle. (4) Masking and misusing the safety time. People who do the tasks used to add safety time by inflating the time estimate for individual tasks. However, inflating the time estimates, in turn, leads to Parkinson‘s Law (not reporting on early finishes and work expands to fill the available capacity) and student syndrome. These effects cause the safety to be misused and masked. Misusing (or wasting) the safety time leads to missing the commitments. Consequently, OTD improvement programs should first focus on improving the mode of project planning and execution instead of reducing task time variability.
We realized unless it is experienced by managers themselves, we could not convince them that these problems (originating outside the projects or uncertainty) do not appear to be the root cause of poor OTD and long PLT in multi-project management; rather, the mode of managing multi-projects does. Their lack of confidence would linger. Continually seeking and trying new management methods or can do little mentality, eventually becomes the norm. Because of the difficulty in overcoming this obstacle through the collection and analysis of data obtained from directly in the field, we invited experienced project managers, resources managers, and engineers to participate in an experiment with a series of multi-project management games. Game 1 was designed to reveal how teams manage the multi-project game with no problems outside of the project. Results were collected to identify the root cause of poor OTD, and served as a baseline to make comparisons with the other games. Games 2 and 3 were designed to gather data to support the notion that ―mode of managing multi-projects‖ was the root cause and to validate that changing the mode of managing multi-projects (CCPM) could significantly improve OTD and PLT. Such measures include reasonable and reliable project plans (more efficient use of safety time embedded in each task), reductions in bad multi-tasking, prioritizing or working on the right priority (with a buffer management system), changing work behaviors (such as those related to student syndrome or Parkinson‘s Law). This is the first objective of the thesis.
Concerning the critics from academia, two major criticisms include the shortcomings and lack of novel ideas in CCPM. Concerning the first critic, one of the most significant shortcomings in CCPM claimed by them is the lack of mathematical analysis, specifically, in buffer sizing determination (Ashtiani 2007, Liu 2008, Long and Ohsato 2008 and Rezaie 2009), critical chain identification (Long and Ohsato 2007, Cui 2010 and Zhen Yu Zhao 2010),
and priority control (Cohen, Mandelbaum and Shtub 2004). The results of newly developed methods tested for validity show that the proposed methods yield schedules that are more reliable in duration estimation and priority control than the schedules produced by the original CCPM method. By answering this critic, Goldratt (1997, 2008) and Steyn (2000, 2002 ) emphasize that due to uncertainty and unavailability of accurate data on task duration, optimizing buffer size, critical chain schedule, and priority control is a myth. They proposed that buffer management is the key to managing uncertainty. However, from an academic research viewpoint, these research efforts enhance the theory of the CCPM method.
Concerning the second critic, Duncan (1999) and Trietsch (2005) have argued that although CCPM presents some good ideas as new insights, these ideas are not new. They have claimed that the project management literature has thoroughly documented changing bad human behaviors, such as reducing bad multi-tasking. They also doubts whether it has much to offer when applying the PMBOK (2004) concepts properly. Steyn (2000, 2002), referring to Drucker (1985), mentioned that a large new method is not new knowledge. Innovation is a new perception. It is putting together things that have been around for a long time in a way that no one has thought of putting together before. His study concluded that CCPM puts together concepts that have not been combined in the same way before, and is therefore considered an innovation. Steyn‘s study presents that CCPM achieves highly reliable OTD (On Time delivery) and short PLT (Project Lead Time) in a multi-project environment mainly because it makes good use of safety time imbedded in tasks by implementing two changes: logistical change (plan aggressive task times with 50% buffers, stagger the release of projects, determine priorities with buffer management) and bad human behavior change (no bad-multi-tasking, no student syndrome and no Parkinson‘s Law).
Yuji (2010) in his book claims by applying logistical changing aligned with performance measurement change and buffer management creates a situation in which good behaviors become more desirable. For example, giving people ―aggressive but possible‖ task duration and not judging the ability of people to meet their time estimates reduces the student syndrome and Parkinson‘s Law. People who are given ―aggressive but possible‖ task duration cannot accept additional tasks at the local level and senior management cannot easily add additional tasks to them because they do not have their own safety time. Multi-tasking reduces in both situations. Logistical change staggers each project as late as possible with a synchronization buffer and schedules the non-critical chain as late as possible with a feeding buffer. Both reduce multi-tasking behavior. Switching a resource between tasks only when a
project buffer erodes to the extent that it poses a risk of delaying a project further avoids multi-tasking, as well as setting priorities only according to the degree the task consumes its project (or feeding) buffer. Buffer management of CCPM determines the priority of a task by examining its affect on project completion. Bendoly and Swink (2007) also supported that lack of timely information affects the behaviors of project managers in ways that do not directly focus on work objectives, but that affect performance.
Steyn also indicated that the assumptions regarding bad human behaviors are not critical to CCPM validity, unlike logistical change. However, Steyn did not adequately support that assumption. Leach (1999) also indicated that although applying the CCPM increases OTD and reduces PLT successfully, it is still difficult to determine to what extent the CCPM or the mere emphasis on logistical change contributes to success.
Although Goldratt (1997b, 2003) with his simulation results pointed out that mere emphasis on logistical change CCPM outperforms with no logistical change in terms of OTD and short PLT (Table 1.1).
Table 1.1 Compare the simulator results
Days until project completion
Chance to complete 10% 50% 90% CCPM Project 1 80 95 115 Project 2 140 160 180 Project 3 170 190 210 With no logistical change Project 1 95 111 131 Project 2 151 171 201 Project 3 178 198 222
By carefully examining Goldratt‘s simulation model, which was designed according to the scheduling rule in which the first task of each project path starts only at the planned start time (Figure 1.1), even if it can be started early (as late as possible). This rule favors CCPM because the starting time of the first task of each project path planned by CCPM will be started earlier than those planned with no logistical change.
( FB: Feeding Buffer)
(a)
(b) Figure 1.1 (a) CCPM Single Project Plan, (b) Single Project Plan with no logistical change
Does the mere emphasis on logistical change contribute to the success of project reduction and OTD improvement? To answer this question, a multi-project management simulation experiment was designed to conduct a comparative study of the critical chain and PERT planning method, without bad human behaviors. Because the planning (project time estimation) and execution methods affect the success of PLT reduction and OTD, we first compared the CCPM method with the PERT method to evaluate the planning results of the two methods regarding the same project networks and uncertainties. Second, we simulated both plans to evaluate OTD performance under different scheduling rules. This is the second objective of the thesis.
2. Literature reviews 2.1 Fundamental of CCPM
Critical Chain Project Management (CCPM) is a methodology for planning, executing and managing projects in single and multi-project environments. Critical Chain Project Management was developed by Dr Eli Goldratt and was first introduced to the market in his Theory of Constraints book ―Critical Chain‖ in 1997(Goldratt 1997a). It was developed in response to many projects being dogged by poor performance manifested in longer than expected durations, frequently missed deadlines, increased costs in excess of budget, and substantially less deliverables than originally promised.
The CCPM achieves highly reliable OTD and short PLT in a multi-project environment mainly because it makes good use of safety time imbedded in tasks by implementing three changes: logistical change, human behavior change and buffer management.
Logistical change
Logistical changes were performed by applying CCPM, Critical chain planning and buffering method. The theory behind the CCPM is that safety time embedded at the task level prolongs the project without providing sufficient safety for project completion, and tends to promote negative human behavior and bad multi-tasking. The greater the degree of uncertainty, the greater the safety imbedded in the time estimates for each task, which leads to more severe negative human behavior and bad multi-tasking. In the vast majority of project environments, safety represents at least half of the time estimate. Shifting safety from the tasks (this gives ―aggressive but possible or most likely‖ 50/50 task duration) to the end of their respective task sequences (paths) places safety in a position where it should be, and requires much less safety than the sum of safeties removed from the tasks. To encourage resources working on ―aggressive but possible‖ task time requires no longer judging resources by their ability to meet their time estimates, which further requires a performance measurement change. In other words, resource must recognize that, except for the project due date, the schedule indicates targets or expected durations rather than commitments or milestones. The CCPM method consists of two major steps: (1) Building a critical chain plan for each single project from its project network and (2) Staggering projects.
The steps involved in building critical chain plans from a project network include: (1) Lay out everything for the project network-push as late as possible, to determine where resource contention may fall. (2) De-conflict contention. (3) Identify critical chains—the
Critical Chain is defined as the longest chain [not path] of dependent tasks. In this case, ‗dependent‘ refers to resources and resource contention across tasks/projects as well as the sequence and logical dependencies of the tasks themselves. This differs from the Critical Path Method. (4) Insert project buffer—a project buffer is inserted at the end of the project network between the last task and the completion date. Any delays on the longest chain of dependant tasks will consume some of the buffer but will leave the completion date unchanged and so protect the project. The project buffer is typically recommended to be half the size of the safety time taken out, resulting in a project that is planned to be 75% of a ―traditional‖ project network. (5) Insert feeding buffer—everywhere a non-critical chain path or task dependency exists, requires a feeding buffer. Delays on paths of tasks feeding into the longest chain can impact the project by delaying a subsequent task on the Critical Chain. To protect against this, feeding buffers are inserted between the last task on a feeding path and the Critical Chain. The feeding buffer is typically recommended to be half the size of the safety time taken out of the feeding path. Figure 2.1 illustrates the steps of critical chain planning.
Step 1 Layout as late as possible Step 2.1 De- conflict contention:D1-D/H2-D
Step 2.2 De- conflict contention: Step 3 Identify critical chains: A1-Y/C2-Y/G2-Y B1-A1-G2-C2-D1-D2-A4
Step 4 Insert project buffer and feeding buffer (half the size of the safety time taken out from the task )
The steps involved in staggering projects include: (1) Select the resource with the highest load and (2) Stagger the projects according to the highest loaded resource to determine the starting time of the first task of each project path and the project delivery date. Because time estimates are cut in half, one of the important elements in staggering projects properly is to ensure enough staggering caused by the schedule of the ―highest loaded resource‖ (referred to as drum schedule in CCPM) to minimize peak loads on the other resources (possibly caused by bad multi-tasking again). To ensure this, a time buffer (called a synchronization buffer) was added to the schedule of the ―highest loaded resource.‖ This time buffer also prevented any negative variability in accomplishing the drum tasks in one project from influencing the start of drum tasks in another project. The CCPM utilized up to 100% of the safety that was formerly in the drum task estimates and reallocated the safety to the synchronization buffer. Figure 2.2 shows the steps of projects staggering.
Step 1 Three similar projects before staggering Step 2 Identify the highest loaded resource type: Red (R)
Step3 Stagger the projects according to Step 4 Insert Synchronization buffer the highest loaded resource
Step 5 Multi-project planning result of CCPM
Human behavior change
Uncertainty is the nature of the project task. Experience shows that safety is necessary to protect the due date and to avoid disappointing people. However, how can people work with the safety? How do people work when there is even a little safety? People may think there is still time until the due date, and be slow to start the task. Then, when they approach the deadline, they cram to make the deadline. This is the so-called student syndrome (delay the starting time to lengthen the duration time). To make matters worse, Parkinson‘s Law states that people will always use the given time and expand work to fill the available capacity. Both behaviors result in misusing and masking the safety time, which leads to missed commitments.
Further more, in multi-project environment, releasing projects too early causes too many projects to be executed simultaneously. This means working under pressure on more than one task at a time, making multi-tasking unavoidable. Prolific bad multi-tasking drastically increases the lead-time of tasks and projects, which leads to further missed commitments. The lack of clear priorities combined with the fear of not finishing projects on time also leads to multi-tasking.
To avoid these three bad human behaviors, CCPM advocates that logistical change, aligned with performance measurement change and buffer management, creates a situation in which good behaviors become more desirable. For example, giving people ―aggressive but possible‖ task duration and not judging the ability of people to meet their time estimates reduces the student syndrome and Parkinson‘s Law. People who are given ―aggressive but possible‖ task duration cannot accept additional tasks at the local level and senior management cannot easily add additional tasks to them because they do not have their own safety time. Multi-tasking reduces in both situations. Logistical change staggers each project as late as possible with a synchronization buffer and schedules the non-critical chain as late as possible with a feeding buffer. Both reduce multi-tasking behavior. Switching a resource between tasks only when a project buffer erodes to the extent that it poses a risk of delaying a project further avoids multi-tasking, as well as setting priorities only according to the degree the task consumes its project (or feeding) buffer. Buffer management of CCPM determines the priority of a task by examining its affect on project completion. Bendoly and Swink (2007) also supported that lack of timely information affects the behaviors of project managers in ways that do not directly focus on work objectives, but that affect performance.
Buffer Management
CCPM uses buffer management during project execution to answer two main questions: (1) Which task do task managers work on next? (2) When do project managers take actions to expedite the project? Tracking CCPM projects requires identifying when tasks start and finish, and obtaining estimates on the remaining duration for tasks in work. The reason to use remaining duration rather than estimates of completion is that humans tend to overestimate the percentage complete. When called upon to look forward and consider the work remaining to complete a task, people tend to make more accurate estimates. Remaining duration is also the actual number needed to estimate project completion, and estimating it directly avoids the assumptions necessary to convert a percent complete estimate to a remaining duration estimate.
CCPM buffer management then uses the estimates of remaining duration for incomplete tasks to calculate the impact of the task status, including the absorption of variation by feeding buffers, to determine how much of the project buffer has been used. The amount each buffer is consumed relative to project progress tells us how badly the delays are effecting our committed delivery date. If the variation throughout the project is uniform then the project should consume its project buffer at the same rate tasks are completed. The result is a project completed with the buffer fully consumed on the day it was estimated and committed. Task managers place priority on the tasks that cause the greatest amount of project buffer penetration. Project Managers determine the corrective actions necessary to ‗recover‘ buffer time at points in the project where the buffer consumption is occurring faster than the project is progressing.
Buffer consumption is monitored daily by the project manager and recovery action taken where necessary Consumption of the buffer indicates a task is exceeding the ambitious time and that the task manager may need assistance. Action at the project level may be needed to recover a situation. Senior managers monitor the status of all projects and take action where necessary. At this level the priority status of all projects is reviewed periodically to monitor and address higher level program recovery. Reasons for delay are monitored and provide focus for improvement. The relevant reasons for delay are extracted to focus improvement activity. Figure 2.3 illustrates a visual buffer management method developed by Holt (2010).
Figure 2.3 Visual Buffer management
2.2 Review of CCPM literature
In the past 15 years, many project management practitioners and researchers have written books (Newbord 1998, 2008, Leach 2004, Yuji 2010 and Goldratt School 2010) and conducted research to enhance and spread CCPM knowledge (Steyn 2000, 2002, Rand 2000, Herrolen and Leus 2001, 2002, Elmaghraby, Herroelen and Leus 2003, Cohen, Mandelbaum and Shtub 2004, Ashtiani 2007, Jacob and Mendenhall 2008, Long and Ohsato 2007, 2008, Liu 2008, Rezaie 2009 and Cui 2010), developed software systems (Realization 2011, Prochain 2011) to support CCPM implementation, and created implementation strategy and tactics to guide practitioners in how to implement CCPM (Goldratt 2008, Goldratt School 2010 and Realization 2011). The literature has also reported hundreds of successful cases achieving highly reliable on-time delivery with short project lead-time in a multi-project environment (Realization 2011, TOCICO 2011, Goldratt Marketing Group 2011).
The main distinction between CCPM and traditional project management is well reported (Newbold 1998, Leach 1999, Umble and Umble 2000, Steyn 2000). Pittman (1994) and Walker (1998) examined the single and multiple project environments (respectively) sought to expose the assumptions and practice of scheduling and controlling projects by traditional methods. Hoel and Taylor (1999) sought to provide a method (via simulation) for determining the appropriate size for the buffers required by CCPM. Ran (2000) introduced CCPM to the project management literature framing CCPM as an extension of TOC. He concluded that CCPM not only dealt with the technical aspects of project management (like PERT/CPM) but also that CCPM dealt with how senior management manages human behavior in the construction of the project network as well as the execution of the network.
Steyn (2000) followed this research with an investigation of the fundamentals of CCPM. He concluded that a major impediment to implementing CCPM is that it requires a fundamental change in the way project management is approached and that such a change is likely to meet with resistance. Lechler et al. (2005) acknowledges the clear benefits but highlights the challenge in adopting a different mindset and suggests it could explain some failures. The issues include the greater discipline of having activity times with the buffers removed and the complexity of managing multiple buffer types.
Despite this positive information, however, there are questions over whether elements of the design are original to Goldratt. Trietsch (2005) is most critical in this area goes into some detail on the elements of the approach he would attribute to others. This includes: (1) earlier reference to resource dependency ‗the critical sequence‘ (Wiest 1964) and general awareness of the need to consider limiting resources in the network plan. It would appear resource dependency was acknowledged academically but this was not effectively incorporated in profession tools before CCPM. (2) The abolition of intermediate due dates which he links back to Schonberger (1981), among others, who was an early proponent of lean and had seen the damage that intermediate dues dates had on traditional batch manufacture. (3) Trietsch acknowledges the important contribution of feeding buffers, but again questions their originality, citing his work as earlier. He suggests project buffers naturally arise under other names as in Obrien‘s (1965) term ‗contingency‘. CCPM is inherently simple in concept, therefore, it would be surprising if the elements had not already been identified. However, even Trietsch (2005) acknowledges Goldratt‘s important contribution in drawing together these elements in a holistic manner as do other more critical authors (Raz et al., 2003). Duncan (1999) also criticized that although CCPM presents some good ideas as new insights, these ideas are not new. They also doubt whether it has much to offer when applying the PMBOK (2004) concepts properly.
Several authors (Raz et al. 2003, Elton and Roe 1998) also argue the approach brings more discipline but raise reservations over downplaying the traditional importance of personal project management skills. Raz et al. (2003) also suggests the industrial successes are due to the adoptions being in organizations who have poor project management implementations in the first place. However, no empirical evidence was offered and the growth in applications, and the case research reported here.
for a change in the organizational culture works against this approach. For example, the need to give up task time ownership, not use task due dates and avoiding multi-tasking. Again no research evidence is offered but these issues are explored in the case research that follows.
Raz et al. (2003) questions the stability of a bottleneck resource within a project environment as does Trietsch (2005). He quotes the work of Hopp and Spearman (2000) in questioning the merits of DBR over CONWIP arguing that CONWIP is less susceptible to bottleneck instability. Although this critique was not directed at CCPM the instability of the bottleneck resource in project management has more recently been acknowledged by Goldratt (2007). His original guidance (1997) was to plan projects around a ‗drum‘ in the form of a resource. This has now been changed to a virtual drum resource that acknowledges any limiting resource is likely to move and the real issue in projects is not resource constraints but synchronization (2007). It is intended that this new development will be closely investigated through this research if the opportunity arises.
Several authors raise question over the sizing of buffers to comprise one third of the path duration. It needs to be acknowledged that there is no scientific bases for the buffer sizing but it is clear the size of the buffer required depends on several factors, including frequency of updates, task uncertainty and project service level. A proposal to size a buffer using a fixed as well as a variable element (Raz et al., 2003) is an interesting possibility but Goldratt advocates that even in construction where uncertainty is relatively low the generic sizing rule still holds as the buffer is a natural extension of the task time. Although this results in an inherently simple policy there are clear merits in simplicity, but undoubtedly further justification is desirable. These matters will be closely monitored in the design of the case research that follows, however, we need to determine whether the any additional complications add significant value. Raz et al. (2003) also question the validity of the assumption that tasks are routinely overestimated then wasted as well as the practicality of extracting the buffer time from the task estimates. They suggest that transferring some of the estimate to the buffer will reduce commitment or encourage further escalation of the task time estimates. Again, this claim is central to the CCPM approach and will be specifically investigated in the case research.
Concern is also raised over the use of a buffer penetration ratio for priority setting, arguing that other factors such as project value could be more important. This argument is indeed valid if it is assumed not all projects can be finished on time. Herroelen and Leus
(2001) conducted computational experiments and argued the buffer sizing can be improved by ‗clever project scheduling methods such as branch and bound’. They suggest such ‗advanced project scheduling tools can be implemented as black boxes without forcing management or workers to know the technical details of the scheduling mechanism involved’. Further work is clearly warranted here but due consideration needs to be given to the uncertain nature of the real world and the benefit of simple pragmatic solutions that work with the full engagement of management rather than the use of ‗black box‘ logic.
Herroelen, Leus, and Demeulemeester (2001) continued much of the same argument in a later paper. Likewise, Raz, Dvir, and Barnes re-examined CCPM and concluded that project performance is often a function of the skills and capabilities of project leaders and that ―some CCPM principles do make sense in certain situations‖ (2003). McKay and Morton (1998) as well as Pinto (1999) were concerned that CCPM might be misapplied by managers who failed to understand the underpinnings of CCPM and who attempted to adopt it without full changing their fundamental approach to the management of projects.
Answering this criticism, Steyn (2002) sought to apply TOC to a variety of other areas of project management beyond the creation and execution of project schedules. He recognized the multidisciplinary nature of project management and how it affects cash flow, stakeholder needs, and risk management. Yeo and Ning (2002) began work on integrating supply chain management with project management. Sonawane (2004) incorporated systems dynamics with CCPM to create a ―modern‖ project management system. Similarly, Lee and Miller (2004) applied systems thinking to multiple projects along with CCPM, and Trietsch (2005) argued that CCPM is, in fact, a more holistic approach to project management than traditional methods. Goldratt (1997, 2008) emphasize that due to uncertainty and unavailability of accurate data on task duration, optimizing buffer size, critical chain schedule, and priority control is a myth. He proposed that buffer management is the key to managing uncertainty. However, from an academic research viewpoint, these research efforts enhance the theory of the CCPM method.
Cerveny, and Galup (2002) also pointed out that the strength of CCPM is in the ability it gives organizations and project managers to protect project flow from the inevitable uncertainty and variability that cannot be planned out of existence. The focus that knowledge of the constraining resource provides also ensures that appropriate and consistent criteria to prioritize projects, accelerate lead times, and ensure proper resource behavior are aligned. The
TOC/thinking process (TOC / TP) methodology of CCPM is presented as a logically derived, comprehensive, and holistic approach to achieving these desired outcomes. He believes that it provides an alternative, more complete solution for project management that can be implemented.
There are clearly many questions regarding the details underpinning the application of CCPM but the overriding consensus is that CCPM makes a significant conceptual and practical contribution. The process of improvement is ongoing, as illustrated in the S&T developments (Goldratt 2007) discussed later and, as all solutions are underpinned by assumptions it is important to expose those that may prove to be invalid in establishing the boundaries and targeting the improvement process. Trietsch (2005) advocates more scrutiny over the underlying assumptions stressing Goldratt‘s claim ‗it works‘ only means the flawed assumptions are not fatal. This is indeed true and, therefore, what is needed is to identify the fatal flawed assumption first in embarking on a process of ongoing improvement. To do this, however, research needs to be closely allied to practice which is a particular concern in designing the case research that follows.
2.3 CCPM Strategy and Tactics tree Structure of Strategy and Tactics Tree
The TOC Strategy & Tactics tree (S&T tree) developed by Goldratt (2007) is the TOC Thinking Process application for facilitating whole-company ongoing improvement. Goldratt defines strategy as simply the answer to the question ―what for?‖ or ―what is the purpose (the desired effect) of ?‖ Tactics are the answer to the question ―How do we achieve the strategy/desired effect (using a chosen mode of operation)?‖ Based on these definitions, S&T entities always exist together; for different levels, S&T entities exist at each level. This means talking about S&T tree is actually talking about a structure that looks something like that shown in Figure 2.4 (Goldratt 2007). At the top are the strategy and tactics of the highest level. This study will call it the mission statement. Further down the tree addresses how to achieve the mission set out in the mission statement and goes into the functions with greater and greater detail. Each level must provide the answers to ―what for‖ and ―how.‖
The S&T tree is, probably, the most powerful thinking process tool and the logical structure that enables focusing. The S&T trees bring clarity to implementations by enhancing management level communications and synchronizing various departments. The trees considerably shorten the time to reach results and smooth the transition from one
implementation stage to the next. They also enable introducing the detailed implementation plan of TOC solutions into the public domain.
Figure 2.4 (Goldratt 2009): A complete structure of S&T tree Level 1 Level 2 Level 3 Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm. Ncc. Assm. Strat. (Obj) Parallel Assm. Tactic (Act) Suff. Assm.
CCPM Strategy and Tactics tree
Despite hundreds of reported accounts of successful Theory of Constraints (TOC) Critical Chain Project Management (CCPM) implementations (Realization 2011, Goldratt Marketing Group 2011). The concern of CCPM solutions are conceptual only; even success stories lack in depth discussions on how to translate the concept into practice to reach results (how to implement CCPM). Their major concern was the lack of solid implementation steps to effect change. Goldratt acknowledged that TOC CCPM has previously not had solid implementation steps. Consequently, he developed Strategy and Tactics (S&T) trees (Barnard 2008, 2009) to provide step by step guidance for effecting change. Figure 2.5 illustrates the CCPM S&T tree developed by Goldratt (Barnard 2008, 2009). The highest level of the tree shown is the step, ―Meeting project promises‖. Six steps in a group at level two form the necessary steps sufficient to achieve the step a level one, including ―Reducing bad multi-tasking and WIP‖, ―Full kitting‖, ―Critical chain planning and buffing‖, ―Managing execution‖, ―Migrating client‘s disruption‖ and ―Managing sub-contractors or subcontracted sub-projects‖. Going down to level three, there are four steps in a group, ―Freezing‖, ―Accelerate project completion‖, ―Defrost mechanism‖ and ―Releasing of new projects‖, that form the necessary steps to achieve the step ―Reducing bad multi-tasking and WIP‖. The three steps, ―Preparations according to priorities‖, ―Defining preparations‖ and ―Worried clients‖ are necessary for the group to achieve the step ―Full Kitting‖. The other three steps, ―Building good project plans/PERTs‖, ―Building critical chain plans‖ and ―Staggering project portfolio,‖ are necessary for the group to achieve the step ―Critical chain planning and buffing‖. Finally, the four steps, ―Task completion reporting‖, ―Task managers‘ role in managing execution‖, ―Project managers‘ role in managing execution‖ and ―Top management role in managing execution‖ are necessary for the group to achieve the step ―Managing execution.‖
Freezing Accelerate project completion Defrost Mechanism Release of new projects preparations according to priorities Defining Preparations
Worried clients Building Good project Plans/ PERTS Building Critical Chain Plans Staggering Project Portfolio Task Completion Reporting Task Manager‘s Role in managing execution Project Manager‘s role in managing execution Top Management role in managing execution 3.11.1 3.11.2 3.11.3 3.11.4 3.12.1 3.12.2 3.12.3 3.13.1 3.13.2 3.13.3 3.14.1 3.14.2 4.14.3 3.14.4 1
Meeting Project Promises
Reduce Bad
Multi-tasking and WIP
Full Kitting Critical Chain
Planning and Buffering
Managing Execution Mitigating Client‘s disruptions
Managing Sub-Contractors or Contracted Sub-Projects
2.1 2.2 2.3 2.4 2.5 2.6
Figure 2.6a illustrates the strategic and tactic entities of level 1 and level 2. The strategy entity (what for) of level one is ―The Company has very high due-date performance without compromising on the content or on the budget‖, and its corresponding tactic entity (how) is ―The Company implements Critical Chain Project Management (CCPM) culture and procedures‖. To attain the level one objective, ―The Company has very high due-date performance without compromising on the content or on the budget‖, five necessary strategy entities of level two are necessary, including ‖ Flow is the number one consideration (the target is not how many projects the Company succeeds to start working on, rather it is how many projects are completed)‖, ―A project is rarely launched before its preparations are complete‖, etc. Each "Strategy entity" of level two must have a corresponding ―Tactic entity‖ which details the tactic entity, ‖The Company implements Critical Chain Project Management (CCPM) culture and procedures‖ of level one. This includes, ―The Company properly controls the number of projects that are open at any given point in time‖, ―The company uses the window of reduced load on resources that do the preparations to ensure that ―full kit‖ practice will become the norm‖, etc.
Click the button (shown on the bottom in Figure 2.6a) of steps 2.1, 2.2, 2.3 and 2.4 will go down their lower level. Figure 2.6b illustrates the strategy and tactic entities necessary for step 2.1. In order to attain the objective set out in step 2.1, ―Reducing bad multi-tasking and WIP‖, it requires four necessary strategy and tactics entities including 3.11.1 ‖ Freezing‖, 3.11.2 ―Accelerate project completion‖, 3.11.3 ‖ Defrost mechanism‖ and 3.11.4 ―Releasing of new projects‖. Each "Strategy entity" must have a corresponding ―Tactic entity‖ which details the tactic entity of its higher level. Successful implementation of these four steps will lead to successful implementation of step 2.1 Similarly, Figures 2.6c-2.6e show the strategy and tactics necessary to achieve the objectives set out in steps 2.2 ‖ Full kitting‖, 2.3 ―Critical chain planning and buffing‖ and 2.4 ―Managing execution‖.
Figure 2.6a (Barnard 2008, 2009): The details of CCPM S&T tree level 1 and 2 S S S S S S
1 Meeting Project Promises
The Company has very high due-date performance without compromising on the content or on the budget.
Flow is the number one consideration (the target is not how many projects the Company succeeds to start working on, rather it is how many projects are completed).
A project is rarely launched before its preparations are complete
Flow is the number one consideration (it is not important to finish each task on time, it is essential to finish each project on time).
Projects are actively managed to ensure their successful, rapid completion
The Company has very high due-date performance even in cases where client inputs are required and/or specification changes occur.
The Company has very high due-date performance even in cases where sub-projects are contracted. 2.1
Reduce Bad Multi-tasking and WIP
2.2
Full Kitting
2.3
Critical Chain Planning and Buffering
2.4
Managing Execution
2.5
Mitigating Client‘s disruptions 2.6 Managing Sub-Contractors or Contracted Sub-Projects The Company implements Critical Chain Project Management (CCPM) culture and
procedures. T
S
The Company properly controls the number of projects that are open at any given point in time T
The company uses the window of reduced load on resources that do the preparations to ensure that ―full kit‖ practice will become the norm. T
For all projects proper PERT networks are built (using templates where appropriate). The time estimates are cut in half and projects and feeding buffers are inserted according to CCPM. The projects are properly staggered.
Proper actions are taken to ensure that resources are aware that their estimates are regarded as just estimates - they will no longer be judged according to meeting their time estimates.
The resulting plan is used to properly release projects into operations.
The resulting planning ability is used to determine reliable and acceptable due-date commitments for new projects.
T
Critical Chain Buffer Management is the ONLY system used to provide priorities. Priority reports are provided in different forms to different management functions. Mechanisms are set to enable proper usage of the priority information.
T
The client professionals are exposed to the CCPM project network and the logic of its buffers. The Company people who interact with the client are professional at communicating the impact the client actions have on the completion of their project and the resulting damage. The mechanism is in place to adjust due-date commitments when applicable.
T
The Company provides on-going focus to the sub-contractors. When appropriate, the
Company is careful to provide the right incentives for satisfactory on-time performance to its sub-contractors. T Click to further lower level
S
1 Meeting Project Promises
Flow is the number one consideration (the target is not how many projects the Company succeeds to start working on, rather it is how many projects are completed).
2.1
Reduce Bad Multi-tasking and WIP
2.2 Full Kitting 2.3 Critical Chain Planning and Buffering 2.4 Managing Execution 2.5 Mitigating Client‘s disruptions 2.6 Managing Sub-Contractors or Contracted Sub-Projects
The Company properly controls the number of projects that are open at any given point in time
T
3.11.1 Freezing
The number of open projects is quickly reduced to be more inline with better flow and throughput.
S
The top manager in-charge of all projects, after consulting with his subordinates, determines the prioritization of projects and instructs to freeze (cease activities on) enough* of the lowest priority projects.
* ―Enough‖ means: responsible for at least 25% of the load.
The proper actions are taken to ensure full adherence to the freezing decision.
T
3.11.2 Accelerate project completion 3.11.3 Defrost Mechanism 3.11.4 Releasing of new Projects
There is good (sufficient for accelerate project completion) assignment of resources to projects.
S
T
The optimal number of the various types of resources needed for each open project is determined. The freed resources are used to prudently strengthen the open projects.
Proper manning decisions are also done for the frozen and to be released projects.
Frozen projects are defrosted at a pace that maintains the reduced load
S
The company chooses integration (or part of it) as the VIRTUAL DRUM : The number of projects allowed in that section is restricted to be, at most, 75% of the current number. When a project completes this integration a frozen project is defrosted. The sequence of defrosting projects is according to the agreed projects prioritization.
T
The timing for the release of each ―leg‖ of a new project takes into account the lead-time of the leg.
S
T
When the time arrives to release new projects, steps 2.2 and 2.3 should be in place. At that stage, a system to release new projects using the CCPM concepts is ready.
1 Meeting Project Promises
2.1
Reduce Bad
Multi-tasking and WIP
2.2
Full Kitting
3.12.1 Preparations according to priorities
Resources and project leaders are used to working on projects whose preparations are (almost) fully completed. S
A Full-Kit manager is appointed. The relevant resources are instructed to complete the preparation steps first for the running - not frozen - projects. Then to complete the preparations for frozen projects. Only when (most of) the above is done they are guided to work on the
preparations for the new projects waiting to be released. They always follow the projects priority.
T
3.12.2 Defining Preparations 3.12.3 Worried Clients
The permission (or even demand) to work on preparations does not violate the freeze and/or controlled release intentions.
S
T
The activities which should be titled preparations are officially defined as such.
The company takes the actions to ensure that resources (those conducting the preparations and project managers of frozen and unreleased projects) are guided and monitored to work only on the preparation activities as defined.
The threat of loosing projects due to a late start is alleviated.
S
The Company relentlessly completes all preparations (closes the gaps) on running and frozen projects.
T
A project is rarely launched before its preparations are complete
S
The company uses the window of reduced load on resources that do the preparations to ensure that ―full kit‖ practice will become the norm. T 2.6 Managing Sub-Contractors or Contracted Sub-Projects 2.5 Mitigating Client‘s disruptions 2.4 Managing Execution 2.3 Critical Chain Planning and Buffering
S All projects about to be released have PROPERLY detailed PERTs.
1 Meeting Project Promises 2.3 Critical Chain Planning and Buffering
3.13.1 Building Good Project Plans/ PERTS
All relevant projects (projects which are not to be soon completed and the projects to be released in the near horizon) are considered in order to determine the generic projects.
Proper teams construct the templates per each generic project making sure that the resulting PERT will be PROPERLY detailed.
Per each relevant project enough uninterrupted time is devoted by the project-planning-team (the key people that constructed the template and the key project people), to PROPERLY modify the template to fit the specific project.
T
3.13.2 Building Critical Chain Plans 3.13.3 Staggering Project Portfolio The company uses
Critical-Chain-PERTs that enable on-time, faster project completion. S
T
A CCPM workshop is conducted for all people participating in the
project-planning-teams. For each relevant project the project-planning-team continues by following the Critical-Chain process to turn the initial PERT into a Critical-Chain-PERT.
The templates are finalized.
Projects are planned to ensure effective operation. S
A proper team invests the time needed to emulate the VIRTUAL DRUM and to identify and correct the crucial data errors.
Actions are taken to ensure that projects are released according to the plan (legs having different lead-times are released at correspondingly different dates). Actions are taken to ensure that due dates for new
projects are committed ONLY according to the STAGGERING mechanism (or top management‘s decision to postpone a specific existing project). T
Flow is the number one consideration (it is not important to finish each task on time, it is essential to finish each project on time).
S
For all projects proper PERT networks are built (using templates where appropriate). The time estimates are cut in half and projects and feeding buffers are inserted according to CCPM. The projects are properly staggered.
Proper actions are taken to ensure that resources are aware that their estimates are regarded as just estimates - they will no longer be judged according to meeting their time estimates.
The resulting plan is used to properly release projects into operations.
The resulting planning ability is used to determine reliable and acceptable due-date commitments for new projects. T 2.6 Managing Sub-Contractors or Contracted Sub-Projects 2.5 Mitigating Client‘s disruptions 2.4 Managing Execution 2.2 Full Kitting 2.1 Reduce Bad Multi-tasking and WIP
3.14.3 Project Manager’s role in managing execution
1 Meeting Project Promises 2.4
Managing Execution
3.14.1 Task Completion Reporting
The required data is always adequately available. S
Proper explanation is given to all task managers: what is required from them to report on a daily basis, how this information is going to be used and that they will, at last, be able to obey ONLY the formal priority list. The company launches the daily
reporting (by task managers - not by the resources) procedure and relentlessly enforces it.
T
3.14.2 Task Manager’s role in managing execution
3.14.4 Top Management role in managing
execution
Tasks are executed according to their priorities. Preparations and corrective actions are taken in due time.
S
T
Following the priorities, task
managers assign the optimal number of resources to tasks.
Task managers review daily two lists of tasks (open and incoming) and according to the up-to-date priorities make sure tasks are effectively progressing.
Top management is well informed and in full control.
S
Top management reviews periodically (every two weeks) the projects‘ status. For projects whose progress is not satisfactory, the recovery actions are examined.
T
Projects are actively managed to ensure their successful, rapid completion.
S
Critical Chain Buffer Management is the ONLY system used to provide priorities. Priority reports are provided in different forms to different management functions. Mechanisms are set to enable proper usage of the priority information.
T
S
T
Project managers are driving a ―project buffer recovery‖ process for cross departmental actions and exceptions not handled by task management.
Project managers review daily the list of tasks penetrating the most into the project buffer and check if recovery actions are taken or required to ensure that the project is effectively
progressing.
In extreme cases the project‘s Critical Chain PERT (and even the template) are updated. 2.6 Managing Sub-Contractors or Contracted Sub-Projects 2.5 Mitigating Client‘s disruptions 2.1 Reduce Bad
Multi-tasking and WIP 2.2 Full Kitting 2.3 Critical Chain Planning and Buffering
In addition to strategic and tactic entities, other components can be added to each step, and all can be considered as explanations: necessary assumption (explains why the given step is necessary (as part of the group) to achieve the higher step), parallel assumption (explains why the step‘s tactic will achieve the step‘s strategy) and sufficient assumption (explains why all the steps of the corresponding lower level are sufficient to attain this step). Figure 2.7 illustrates all the information necessary to form the ―Reducing bad multi-tasking and WIP‖ step. Detailed information of each step of the CCPM S&T tree can be found in (Goldratt 2007).
2.1 Reduce Bad Multi-Tasking & WIP
Necessary assumptions
When too many projects are executed simultaneously many resources will find themselves under pressure to work on more than one task － bad multi-tasking is unavoidable.
Prolific bad multi-tasking significantly prolongs each project‘s lead-time.
Strategy Flow is the number one consideration (the target is not how many projects the Company succeeds to start working on, rather it is how many projects are completed).
Parallel assumptions
The statement, ―the earlier we start each project, the earlier each project will be finished,‖ is not correct for multi-project environments (not only the first elephant but also the last elephant will go through a door much faster if they go in procession).
Vast experience shows that in multi-project environments, reducing the number of open projects can reduce bad multi-tasking without causing starvation of work and therefore significantly reduces the lead time of all projects － it increases the flow.
Tactic The Company properly controls the number of projects that are open at any given point in time
Sufficiency assumption
Adjusting the amount of work is not enough. The company must also ensure that as time passes the proper amount of work will be always maintained.
