Deck 11: Critical Chain Project Scheduling

Question 1

An important element in critical chain scheduling is to change from a late-finish (procrastination) approach to an early-start approach.

Answer 1

False

Question 2

Critical Chain Project Methodology __________ risk for the entire project.

Answer 2

aggregates

Question 3

An organization's budget estimating process routinely misses the actual cost of a project by 25%. For the most recent project, the budget variance was a ridiculous 23%, but this must be considered common cause variance.

Answer 3

True

Question 4

The __________ Theorem states that if a number of probability distributions are summed, the variance of the sum equals the sum of the variances.

Question 5

Project managers often add a(n)__________ to individual workers' estimates of activity duration.

Question 6

Both positive and negative variation are usually passed downstream during a project.

Question 7

The legal department is needed to review all contracts a project organization enters. The legal department is continually swamped with work and all other departments find themselves waiting on legal before they can begin their work. Legal is the drum for this organization.

Question 8

A(n) __________ refers to a safety margin separating different projects scheduled to use the same resource.

Question 9

Critical Chain Project Management is based on the __________.

Question 10

Once the organization elevates its constraint, its system has no constraint.

Question 11

The critical chain is usually the same as the critical path.

Question 12

If people believe that they built extra time into their initial estimates, they are usually more likely to begin project work right away.

Question 13

In order to estimate completion of a Gaussian distributed activity with a 90% or higher degree of confidence, the time may be overestimated by as much as 200%.

Question 14

__________ is variation that is a fact of life in the normal course of system operation.

Question 15

The Central Limit Theorem states that if a number of probability distributions are summed, the variance of the sum equals the sum of the variances of individual distributions.

Question 16

A feeder buffer is a buffer that is created for a non-critical path activity.

Question 17

Project personnel often become involved in several activities simultaneously; this __________ has negative consequences for the timely completion of these activities.

Question 18

CCPM advocates putting off non-critical activities as late as possible and providing each activity with a(n) __________.

Question 19

Delays in project activity are known as __________ variation.

Question 20

In classic project management, activity durations are estimated based on a(n) __________% likelihood of successful completion, but in CCPM, activity estimates are at the __________% level.

Question 21

Which of the following is an example of common cause variation?

A) Your travel time to work varies between 15 and 20 minutes each way.
B) On the day you return from vacation, there are over 800 e-mails waiting for you in your in-box.
C) An ice storm causes the shipment of steel girders to arrive a week late.
D) Your alma mater begins the football season 4-0 for the first time ever and prices for Homecoming football game tickets go through the roof.

Question 22

In applying the principle of common cause variation to the theory of CCPM, it is important to:

A) not make adjustments to projects when the variation in project performance lies within the range of common-cause variance.
B) immediately call meetings for all key stakeholders if common cause variation is detected.
C) include special cause variation in project risk simulation since there is a chance it may occur.
D) perform risk management on aggregated project risks.

Question 23

According to CCPM:

A) using a point estimate for activity times is the best approach to project duration estimation.
B) the primary causes of inaccurate duration estimation are behavioral in nature.
C) there are a number of ways that project members should add safety to estimated lengths of activities.
D) there are a number of ways that project members should add buffer to the estimated length of activities.

Question 24

All five members of a project team add 10% to their individual serial activities as a safety margin and submit their time estimates to the project manager. The manager adds the activity length estimates together and adds 10% for his personal safety margin. Then, anticipating a cut by top management, he adds another 20% to his final project estimate. Much to his surprise, top management cuts only 10% off his time estimate. How much of a cushion is now built into the project?

A) 25%
B) 31%
C) 56%
D) 88%

Question 25

All five members of a project team add 15% to their individual serial activities as a safety margin and submit their time estimates to the project manager. The manager adds the activity length estimates together and adds 10% for his personal safety margin. Then, anticipating a cut by top management, he adds another 10% to his final project estimate. Much to his surprise, top management cuts 30% off his time estimate. How much of a cushion is now built into the project?

A) 13%
B) 7%
C) 5%
D) -3%

Question 26

In order to estimate completion of a Gaussian, or lognormal, distributed activity time with a 90% or higher degree of confidence, the time may be overestimated by as much as:

A) 20%.
B) 80%.
C) 160%.
D) 200%.

Question 27

In applying the principle of common cause variation to the theory of CCPM, it is important to:

A) do nothing.
B) immediately call meetings for all key stakeholders if common cause variation is detected.
C) include special cause variation in project risk simulation since there is a chance it may occur.
D) perform risk management on discrete project risks.

Question 28

All five members of a project team add 20% to their individual serial activities as a safety margin and submit their time estimates to the project manager. The manager adds the activity length estimates together and adds 20% for his personal safety margin. Then, anticipating a cut by top management, he adds another 20% to his final project estimate. The executive level of the organization just completed a retreat where they read The One Minute Manager, Who Moved My Cheese, and Critical Chain. They return from their retreat both energized and much wiser in the ways of project management. They know that everyone has been routinely adding 20% and want to scale the project back to an unpadded estimate. How much should they cut?

A) 42%
B) 60%
C) 33%
D) 27%

Question 29

The best thing a project manager can do when noticing common cause variation in a project's monthly budget summary is to:

A) call another meeting and brainstorm causes for the variance.
B) call the workers responsible for the variance into the office and dismiss them immediately.
C) do nothing.
D) call the suppliers responsible for the increased cost and negotiate lower material costs.

Question 30

The first step in TOC methodology is to:

A) identify the constraint.
B) exploit the constraint.
C) subordinate the system to the constraint.
D) elevate the constraint.

Question 31

All five members of a project team add 20% to their individual serial activities as a safety margin and submit their time estimates to the project manager. The manager adds the activity length estimates together and adds 20% for his personal safety margin. Then, anticipating a cut by top management, he adds another 20% to his final project estimate. Much to his surprise, top management cuts only 10% off his time estimate. How much of a cushion is now built into the project?

A) 62%
B) 74%
C) 56%
D) 42%

Question 32

Which tendency is not a contributing factor to the student syndrome?

A) People minimize responsibilities with long end-date completions in favor of more immediate critical deadlines.
B) People that believe that extra time has been built into an estimate will be demotivated from addressing these commitments early.
C) High demand people must routinely juggle their schedules to accommodate multiple commitments, which prevents them from addressing tasks with long deadlines.
D) People realize that once a good or service has been provided, it can be difficult to collect compensation for their efforts.

Question 33

XYZ project organization has one workstation that is capable of generating the drawings that their clients study before accepting XYZ's bid. XYZ is currently in the midst of three proposal projects and knows exactly when it will need to use the workstation. All other work to be done, both before and after the workstation is used, is scheduled such that it flows to the workstation and keeps it busy. Resources used after this step are less critical; so while the subsequent work and resources are important, they aren't viewed with the same reverence as the workstation. This is an example of:

A) identifying a constraint.
B) elevating a constraint.
C) subordinating a system.
D) exploiting a constraint.

Question 34

ABC project organization has one workstation that is capable of generating the drawings that their clients study before accepting ABC's bid. ABC is currently in the midst of three proposal projects and knows which proposed project will be most profitable and which will be least profitable. The workstation is scheduled so that the most profitable project's work is done first and the least profitable project work is done last. This is an example of:

A) identifying a constraint.
B) exploiting a constraint.
C) elevating a constraint.
D) subordinating a system.

Question 35

Keith welds a one-fourth-inch diameter ball bearing and a three-eighths-inch diameter ball bearing on each end of an eighth-inch diameter cylinder. Sure, the work is tedious, but he knows he's doing his part keeping this country running and lining his employer's pockets with sweet cash. His employer hopes to speed up this activity by hiring another skilled worker and in doing so, will:

A) subordinate the rest of the system.
B) identify the constraint.
C) exploit the constraint.
D) elevate the system constraint.

Question 36

When individual activity lengths are overestimated:

A) their individual errors tend to cancel out so that the overall project is completed as estimated.
B) the project completion time is grossly underestimated.
C) the project completion time is overestimated.
D) there is no effect if the estimation is done using point estimates for activity lengths.

Question 37

Which of these is Parkinson's Law?

A) Don't put off what you can do today.
B) Once begun, half done.
C) Work expands to fill the time available.
D) People don't plan to fail, they fail to plan.

Question 38

Which of the following is an example of special cause variation?

A) Yesterday the framing crew was a little tired and didn't get as much done as they thought.
B) The avian flu ravaged the laying stock for Chickenverks and the Great Egg Shortage of '06 threatened to cancel Easter egg hunts worldwide.
C) The product unveiling was a week late because there was some difficulty getting the ivory through customs.
D) The debugging step averages two months but this project was finished a day early.

Question 39

The student syndrome of wasting extra safety time can be described as:

A) lack of motivation.
B) procrastination.
C) failure to communicate.
D) lack of comprehension.

Question 40

All five members of a project team add 20% to their individual serial activities as a safety margin and submit their time estimates to the project manager. The manager adds the activity length estimates together and adds 20% for his personal safety margin. Then, anticipating a cut by top management, he adds another 20% to his final project estimate. Much to his surprise, top management leaves his project alone. How much of a cushion is now built into the project?

A) 73%
B) 60%
C) 140%
D) 44%

Question 41

Under the student syndrome model, the slope of the percentage completed curve:

A) increases as the deadline nears.
B) is constant with respect to time.
C) becomes negative as the deadline nears.
D) decreases as the deadline nears.

Question 42

A complex project concludes with three paths merging into a final activity, after which the project is completed. Two of these paths are non-critical and have been managed effectively, with slack remaining. The critical path has also been managed well and is on time entering the merge node. Which statement is best?

A) The merge activity will eliminate the positive slack.
B) The slack will remain with the project unless the final activity is delayed.
C) The critical path method accounts for path convergence.
D) The critical path method tends to overestimate project durations.

Question 43

Which statement about critical chain methodology is best?

A) Activity durations estimated at a 50% level of successful completion are shorter than those estimated at a 90% level of successful completion.
B) Aggregated activity durations at a 90% level of successful completion are shorter than aggregated activity durations at a 50% level of successful completion.
C) The total safety buffer for aggregated activity durations is smaller than the sum of safety buffers for individual activity durations at any likelihood level estimate.
D) None of these statements is correct.

Question 44

Your next project consists of 10 consecutive 8-day activities, each estimated by a different worker in your organization. Note that the estimators have not yet added any buffer to the 8-day figure. Your organizational culture dictates that you add your own safety margin of 30% into your estimates. The new project manager has just completed an excellent course in project management offered at the local university. When the first project meeting begins, he dazzles you with his wit and sophistication. You are considerably less charmed when he reveals that he has an exciting new technique for managing projects. He adheres to critical chain project management ideas and plans to create an overall project safety buffer after trimming the safety buffers from each of the 10 activities. How much closer has the project deadline moved?

A) 12 days
B) 6 days
C) 18 days
D) 9 days

Question 45

A project consists of four consecutive tasks that have average duration and worst-case duration estimates (in days) as shown in the table. Use Newbold's model to determine the aggregated buffer of one standard deviation for this project.

A) 31 days
B) 16 days
C) 8 days
D) 5 days

Question 46

A worker is assigned three tasks, A, B, and C, each having a duration of 20 days. One approach to completing these tasks would be to focus on one at a time, complete it, and then move to the second, followed by the third. One multitasking approach would call for dividing each task into fifths and rotating from one to the other so that the first fifths of A, B, and C are completed before the second fifths of A, B, and C are completed (always in this order) and so on until the activities are finished. What is the difference in the average completion times for the multitasked activities?

A) There is no difference in completion times for the two approaches.
B) The multitasked activities take 15% longer.
C) The multitasked activities take 25% longer.
D) The multitasked activities take 40% longer.

Question 47

A project consists of three activities with information as shown in the table. What is the overall variance of the project?

A) 4.24
B) 8.41
C) 18
D) 24

Question 48

A worker is assigned three tasks, A, B, and C, each having a duration of 20 days. One approach to completing these tasks would be to focus on one at a time, complete it, and then move to the second, followed by the third. One multitasking approach would call for dividing each task into fourths and rotating from one to the other so that the first fourths of A, B, and C are completed before the second fourths of A, B, and C are completed (always in this order) and so on until the activities are finished. What is the difference in the average completion times for the multitasked activities?

A) There is no difference in completion times for the two approaches.
B) The multitasked activities take 15 days longer.
C) The multitasked activities take 15 days less.
D) The multitasked activities take 5 days more.

Question 49

A project consists of four consecutive tasks that have average duration and worst-case duration estimates (in days) as shown in the table. Use Newbold's model to determine the aggregated one sigma buffer for this project.

A) 20 days
B) 10 days
C) 15 days
D) 5 days

Question 50

A worker is assigned three tasks, A, B, and C, each having a duration of 10 days. One approach to completing these tasks would be to focus on one at a time, complete it, and then move to the second, followed by the third. One multitasking approach would call for dividing each task in half and rotating from one to the other so that the first halves of A, B, and C are completed before the second halves of A, B, and C are completed (always in this order). What is the difference in the average completion times for the multitasked activities when compared to the one at a time approach?

A) The multitasked activities take 5 days longer.
B) There is no difference in completion times for the two approaches.
C) The multitasked activities take 5 days less.
D) The multitasked activities take half the time.

Question 51

A worker is assigned three tasks, A, B, and C, each having a duration of 20 days. One approach to completing these tasks would be to focus on one at a time, complete it, and then move to the second, followed by the third. One multitasking approach would call for dividing each task in half and rotating from one to the other so that the first halves of A, B, and C are completed before the second halves of A, B, and C are completed (always in this order) and so on until the activities are finished. What is the difference in the average completion times for the multitasked activities?

A) There is no difference in completion times for the two approaches
B) The multitasked activities take 15% longer.
C) The multitasked activities take 25% longer.
D) The multitasked activities take 40% longer.

Question 52

The Central Limit Theorem says that if a number of probability distributions are summed:

A) the standard deviation of the sum equals the sum of the standard deviations.
B) the variance of the sum equals the sum of the variances.
C) the standard deviation of the sum is greater than the sum of the standard deviations.
D) the variance of the sum is less than the sum of the variances.

Question 53

A project consists of three activities with information as shown in the table. What is the overall standard deviation of the project?

A) 24
B) 18
C) 8.41
D) 4.24

Question 54

A project consists of three activities with information as shown in the table. What is the overall variance of the project?

A) 18
B) 8
C) 2.82
D) 5.56

Question 55

If a project activity experiences negative variation:

A) the following activity can be started earlier than anticipated.
B) the following activity must be started later than anticipated.
C) the preceding activity must be started later than anticipated.
D) the preceding activity can be started earlier than anticipated.

Question 56

Your next project consists of 8 consecutive 8-day activities, each estimated by a different worker in your organization. Your organizational culture dictates that you add your own safety margin of 3 days into your estimates. Unbeknownst to you, the project manager has recently converted to a critical chain project management view. The project manager knows perfectly well what sorts of games are played with activity estimates and she knows exactly how much activity padding takes place. What will the overall project safety margin be once the project manager reviews your estimates and makes the project schedule?

A) 12 days
B) 6 days
C) 18 days
D) 9 days

Question 57

If a project activity experiences positive variation:

A) the following activity must be started later than anticipated.
B) the preceding activity must be started later than anticipated.
C) the following activity can be started earlier than anticipated.
D) the preceding activity can be started earlier than anticipated.

Question 58

If a project activity experiences positive variation:

A) the following activity usually begins immediately on completion of its predecessor.
B) the variation is usually passed downstream to the immediate follower.
C) the variation is usually passed downstream to the most critical activity
D) the variation is usually not passed downstream.

Question 59

A project consists of three activities with information as shown in the table. What is the overall standard deviation of the project?

A) 8.00
B) 4.24
C) 2.82
D) 5.56

Question 60

Your next project consists of 5 consecutive 10-day activities, each estimated by a different worker in your organization. You have all secretly added your own safety margin of 4 days into your estimates and you watch in horror as the project manager whips out his copy of Critical Chain and slams it on the table midway through their first project meeting. "I'm taking your buffers and making them my own," he bellows. You recoil from this news and do some quick mental arithmetic. Now that you know the project manager is a Goldratt disciple, you know that the new project buffer will be:

A) 25 days
B) 20 days
C) 15 days
D) 10 days

Question 61

A project is represented by the activity durations (estimated at 90% likelihood of completion) and precedence requirements shown in the table. What is the length of the feeder buffer for path NQT if this project is managed using critical chain methodology?

A) 9.0
B) 2.25
C) 4.5
D) 6.75

Question 62

In order to resolve a resource conflict, it is advisable to:

A) work backwards from the end of the project.
B) work forwards from the start of the project.
C) begin activities at their earliest possible start time.
D) complete activities at their earliest possible finish time.

Question 63

An important departure from traditional project management is that critical chain project management logic:

A) changes from a late finish to an early start approach.
B) factors in the effects of resource contention.
C) adjusts expected activity durations to reflect a 95% probability of completion on time.
D) creates a separate safety margin for each activity in the project.

Question 64

A project is represented by the activity durations (estimated at 90% likelihood of completion) and precedence requirements shown in the table. What is the length of the feeder buffer if this project is managed using critical chain methodology?

A) 9.0
B) 7.5
C) 4.5
D) 6.0

Question 65

A project is represented by the activity durations (estimated at 90% likelihood of completion) and precedence requirements shown in the table. What is the overall duration of this project if it is managed using critical chain methodology?

A) 22.5
B) 24.75
C) 27.0
D) 33.75

Question 66

A system-wide constraint is called a(n):

A) rope.
B) resource.
C) drum.
D) chain.

Question 67

Use the project information in the table to resolve resource conflicts, identify the critical chain and critical path, and create feeder buffers. The critical chain does NOT pass through:

A) Activity A.
B) Activity F.
C) Activity E.
D) Activity D.

Question 68

Which of the following statement is best?

A) The critical chain requires that all resource leveling be done before the critical chain can be identified.
B) The critical path usually jumps task dependency links.
C) The critical chain relies on task dependency and is discovered after the fact, once the network is laid out.
D) The critical chain is usually the same path as the critical path within an activity network.

Question 69

Subcontractor deliveries are difficult to schedule with the critical chain project methodology because:

A) the project manager cannot force subcontractors to use this project management approach.
B) the feeder buffers for a subcontractor are as much as 50% shorter than for an employee or internal team.
C) subcontractors routinely operate according to calendar delivery dates.
D) the corporate culture of "no blame" does not naturally extend to subcontractors.

Question 70

Use the project information in the table to resolve resource conflicts, identify the critical chain and critical path, and create feeder buffers. A feeder buffer should be placed immediately before:

A) Activity B.
B) Activity F.
C) Activity C.
D) Activity A.

Question 71

A project is represented by the activity durations (estimated at 90% likelihood of completion) and precedence requirements shown in the table. What is the length of the project buffer if this project is managed using critical chain methodology?

A) 13.5
B) 22.5
C) 11.25
D) 9.0

Question 72

CCPM advocates performing all non-critical activities:

A) as late as possible.
B) as early as possible.
C) before starting the critical path.
D) after completing the critical path.

Question 73

A project consists of six consecutive tasks that have average duration and worst-case duration estimates (in weeks) as shown in the table. Use Newbold's method to determine the aggregated two sigma buffer for this project.

A) 5 days
B) 6 days
C) 7 days
D) 9 days

Question 74

A project consists of six consecutive tasks that have average duration and worst-case duration estimates (in days) as shown in the table. Use Newbold's method to determine the aggregated two sigma buffer for this project.

A) 44 days
B) 6 days
C) 17 days
D) 9 days

Question 75

The buffers supplied to non-critical paths in critical chain project management are called:

A) slack buffers.
B) drum buffers.
C) rope buffers.
D) feeder buffers.

Question 76

Use the project information in the table to resolve resource conflicts, identify the critical chain and critical path, and create feeder buffers. The project buffer follows:

A) Activity A.
B) Activity F.
C) Activity E.
D) Activity D.

Question 77

A project is represented by the activity durations (estimated at 90% likelihood of completion) and precedence requirements shown in the table. What is the length of the project buffer if this project is managed using critical chain methodology?

A) 4.5
B) 11.5
C) 20.5
D) 16

Question 78

Which of the following statements about CCPM activity networks is correct?

A) Project workers are more likely to meet a deadline for their activity than miss it.
B) There are no milestones in the CCPM activity network.
C) Project workers are more likely to miss a deadline for their activity than meet it.
D) There is no project delivery deadline in the CCPM activity network.

Question 79

When choosing the most viable solution to resource conflict issues, the best option is the one that:

A) minimizes total network slack.
B) minimizes total network schedule disruption.
C) maximizes total network slack.
D) maximizes activity late start times.

Question 80

A project is represented by the activity durations (estimated at 90% likelihood of completion) and precedence requirements shown in the table. What is the overall duration of this project if it is managed using critical chain methodology?

A) 48
B) 32
C) 64
D) 43.5