1. This work is licensed under a Creative Commons Attribution-NoDerivs 3.0 Unported License.
Critical Chain Project Management
PLAYBOOK LEAN PRODUCT DEVELOPMENT SERIES
PLAYBOOKHQ.co
@PLAYBOOKHQ
2. PLAYBOOK LEAN PRODUCT DEVELOPMENT SERIES
This series is for anyone interested in Lean, Agile and team principles
and how they can be applied in new product development scenarios
to increase innovation, improve delivery times and create engaged,
happy, high-performing teams.
PLAYBOOKHQ.co
@PLAYBOOKHQ
3. Theory of Constraints Elements:
1. Every system has _______________ performance limitation (constraint/bottleneck) at
any time.
2. For example, let’s say we have a serial manufacturing process in which Machine A can
process 100 parts/hr, Machine B can process 20 parts/hr, and Machine C can process
50 parts/hr.
Machine A
100 parts/hr
Machine B
20 parts/hr
Machine B
50 parts/hr
---------->>>>>>>>>>>> Parts Flow --------->>>>>>>>>>>>
a. What’s the maximum number of parts can this line process every hour?
b. _______________ is therefore the constraint and the rest of the system must be
paced off of it.
c. Machine B limits the _______________ of the system.
3. The following process is used to increase system throughput:
a. Identify the constraint.
b. Exploit the constraint.
c. Subordinate all other system elements to the constraint.
d. Elevate the constraint.
e. Repeat the above again, again and again.
4. Identify the Constraint:
1. The goal of the new product development system is to maximize _______________ .
2. _______________ is generally the strongest driver of profit.
3. The constraint/bottleneck of the project is the critical _______________ of the project.
4. Traditional Critical Path says that the speed of the project is determined by the longest
chain of _______________ tasks.
5. If a resource has one critical path task and one non-critical path task scheduled
simultaneously, they are both _______________ .
6. Critical Chain says that the speed of the project is determined by the Critical Chain,
which considers BOTH …
a. _______________ tasks
AND
b. … the limited _______________ needed to execute it.
7. These assume the task durations have been estimated independent of other tasks.
5. Exploit the Constraint (Critical Resource):
1. Maximize the throughput of the _______________.
2. Multitasking _______________ the completion of the critical work.
3. Task buffers artificially inflate the _______________.
4. Don’t waste their time. Make sure they are working with the _______________
information.
5. Make sure they don’t run out of work to do. Keep a prioritized _______________ of
work in front of them. The Critical Resource should know exactly what to work on next.
6. Notes:
1. Task Duration is a function of the Work and resource Availability.
a. Work (hrs) is the total amount of effort involved to complete the task.
b. Availability (hrs/day) is the amount of time a resource has to do the work.
2. What happens to task Duration when the estimated amount of Work changes?
a. Duration varies _______________ with Work.
b. For example, if the estimated amount Work = 12 hrs and we’re available, on
average, 4 hrs/day to do that work…
i.
Duration = 12 (hrs) / 4 (hrs/day) = 3 days
ii. If Work increases 25%, Duration increases _______________.
•
Duration = (12 + 0.25(12))/4 = 3.75 days
•
3.75 days = 3 + x(3)
•
X = 0.25 = 25%
iii. If Work decreases 25%, Duration decreases _______________.
•
Duration = (12 - 0.25(12))/4 = 2.25 days
•
2.25 days = 3 - x(3)
•
X = 0.25 = -25%
iv. What happens if Work changes +50%?
•
+50%, Duration increases _______________.
•
-50%, Duration decreases _______________.
7. Notes:
1. What happens to task Duration when resource Availability changes?
a. Duration varies _______________ with resource Availability.
i. For example, if the estimated amount Work = 12 hrs and we’re available, on
average, 4 hrs/day to do that work…
• If Availability increases 25%, Duration decreases 20%.
• If Availability decreases 25%, Duration increases 33%.
• If Availability increases 50%, Duration only decreases by 33%.
• If Availability decreases 50%, Duration increases by 100%.
2. Implications
a. Task Duration is more sensitive to changes in resource Availability than to changes
in the estimated amount of Work.
b. Even when using good estimates, things will take longer on average than you
estimate.
c. More time is lost when a resource’s Availability goes down than is gained back
when it goes up.
d. Managing & determining resource Availability is very important, especially if it is
low.
e. Keeping resource Availability above 50% will insure much more accurate Duration
estimates.
8. Exploit the Constraint
Method #1 - Minimize Multitasking
1. What is multitasking?
a. When you’re performing multiple Work-type tasks at the same time.
b. When you’re working on a Work-type task during the wait time in a Wait-type
task, you’re not multitasking.
2. Multitasking extends the _______________ of all tasks.
3. The longer the duration, the more…
a. Things _______________ causing some work to be redone.
b. You _______________ what you did and why you did it.
c. Time is spent _______________ between tasks.
d. Time is spent _______________ the status of the tasks.
4. Multitasking can delay a _______________ important task for the sake of a
_______________ important task.
5. Clear _______________ are critical to execute tasks quickly.
6. It is as important to have _______________ priorities as it is to have
_______________ priorities.
a. When task priorities are not clear, we tend to multitask more.
b. How much do we delay Task C by not starting it until A and B are done?
9. Exploit the Constraint:
Method #1 – Minimize Multitasking
1. What happens when we try to work on two things at the same time (i.e. multitask)?
a. Availability for both tasks goes _____________ (half of what it was).
b. What happens to task Duration? _____________ .
c. What is the effect on task Duration of even little changes in Availability?
_____________.
2. When we multitask, we’re operating on the _______________ side of the curve.
3. Is it any surprise that our confidence in task Duration is greatly reduced? __________.
4. Takeaways
a. Organizations that don’t have a good handle on resource Availability have lower
schedule predictability and their projects take longer than desired.
b. Multitasking is a primary contributor to the uncertainty in resource Availability.
10. Exploit the Constraint:
Method #2: Eliminate Task Buffers
1. Task Level Buffers == _______________ estimates for task duration.
2. Safe estimates for task durations make the task take _______________ .
a. Parkinson’s Law - The task grows to fill the time allotted. Engineers continually try
to _______________ the design if they are given the time.
b. _______________ important things come up that make you put off completing the
task.
c. Student Syndrome or just an overly busy, multitasking person, causes
_______________ discovery of problems.
d. And many more...
11. Exploit the Constraint:
Method #2 - Eliminate Task Buffers (continued)
3. If you don’t complete the tasks _______________ as often as you complete them late,
the project will be late.
a. How often are tasks completed early? _______________
b. Why? ____________________________________________________________
4. In summary, task buffers always get _______________ and often the task actually
extends past its buffer.
5. It’s better to _______________ task buffers and instead put a big buffer at the end of
the _______________ .
6. The Project Buffer length is _______________ than the sum of the task buffers.
7. Project Buffers are sized such that they benefit from variability pooling similar to
statistical tolerance analysis.
12. Exploit the Constraint:
Method #2 - Eliminate Task Buffers (continued)
1. A major _______________ change is required to implement and sustain this critical
improvement.
2. Task durations should be estimated as follows: _______________ chance it will be
completed early, _______________ chance it will take longer.
a. Tasks should be completed early about half of the time and take longer half of the
time.
b. Parkinson’s Law will still exist and still cause more tasks to be completed
_______________ more often than they are completed early.
c. Strive to underestimate Duration by 10-20%.
3. Task durations are estimates, NOT _______________ .
a. Do not judge people’s performance on their ability to hit their task duration
estimates.
b. Do not use terms like Due and Late when discussing task status. These terms
imply that the resource has underperformed or not met expectations and will push
the system to more safety which is a _______________ system.
c. Instead, ask, “What is blocking your progress?” or “What is causing the task to
take longer than expected?”.
13. Exploit the Constraint:
Method #2 - Eliminate Task Buffers (continued)
4. Task completion date changes are simply feedback!
a. Some are expected - duration was underestimated (50% estimates)
b. Other causes…
i. Over-utilized resource (decrease of resource Availability)
ii. Too many, frequent, interruptions - not enough productive time (decrease of
resource Availability)
iii. Multitasking (decrease of resource Availability)
iv. External tasks (contractors, suppliers, sterilization…) are not being completed
v. Uncertainty/variability in the amount of effort required (increase of Work).
14. Exploit the Constraint:
Method #2 - Eliminate Task Buffers (continued)
1. Date-driven systems are slow.
a. Work is pushed on the resources resulting in high capacity utilization states and
longer product development schedules.
b. Drive to _______________ instead of dates.
c. You should _______________ hear, “the schedule says we don’t need to do this
until later”.
d. Especially for tasks on the critical _______________.
e. Tasks will usually start later or earlier than originally planned. Be ______________
and ready.
2. Everyone must focus on doing their work in a timely manner with the necessary quality.
3. Track and manage the tasks more easily by…
a. Eliminating task _______________.
b. Maintain clear and visible _______________.
c. Focusing on the _______________ tasks in the daily huddle.
4. Do not use dates as commitments because you fear a laziness problem.
a. Doing so will only encourage safe estimates and _______________ down the
system.
b. It won’t cure the laziness, but instead it will hide the laziness in a larger pile,
batch, of work.
5. Use a Visual Work Management System such as PLAYBOOK to centralize the data,
streamline the process, and put the information at everyone’s fingertips.
15. Subordinate Everything Else to the Constraint (Critical Resources):
1. Use the Critical Resources to set the _______________ of the rest of the development
system.
2. Any activity that uses a Critical Resource can delay the project and therefore is
considered critical.
a. When a Critical Resource needs something from someone else to do their work,
get it to them as soon as possible.
i.
Effectively daily huddles ensure that everyone is aware of these handoffs and
alter their priorities accordingly to provide them with what they need.
ii. Make sure the Critical Resource is working with good data and not working
with insufficient or incorrect data.
b. Consciously minimize interrupting the Critical Resources. On the flip side, if the
Critical Resource needs the time of a Non-Critical Resource, the Non-Critical
Resource should consider the Critical Resource’s work a higher priority.
c. Minimize or eliminate activities that involve the Critical Resources when they are
working on critical tasks, for example: training, performance reviews, planning the
next project or any other lower priority work.
3. Use Slack, the amount of time (in days) a non-critical task can be delayed before it
becomes critical, to set the pace/priority of non-critical tasks.
16. Elevate the Constraint (Critical Resources):
1. Add _______________ to the constraint in order to remove it as the constraint. In new
product development this typically means, raise the capacity of the Critical Resources.
2. Only add capacity if it pays to do so.
a. There is diminishing return for each new resource.
b. There is an optimal number of resources, after which adding more resources
doesn’t help get done the job done faster.
c. New Duration = Original Duration*(# current resources)/(# current resources +
# new resources)
3. When adding resources, you typically need to add some time for them to get up to
speed which adds work to both the new resource and the current resource(s).
4. Adding resources to one group only helps until a different group becomes critical.
a. For example, if 2 EEs have 12 months of work each and Software has 10 months
of work. The EE’s work is critical by 2 months.
b. Adding 1 EE reduces the EE work to 8 months, now Software is critical by 2
months. Adding more EEs won’t result in faster project.
5. It is better to have a single, clear critical chain (group).
a. When several groups are co-critical, there is a lot of priority switching… e.g. who
has priority to interrupt someone during Time Blocking?
b. The Critical Resource can’t be exploited, elevated or subordinated if its changing all
the time.
c. This causes turbulence which disrupts the flow and slows down the system.
17. Notes:
1. Buffer Charts (Fever Charts) are used to track the performance of the project by
tracking the rate of buffer consumption of the project completion or interim milestone.
2. Colors:
a. Green = Ok, on track
b. Yellow = ____________________ intervention
c. Red = ____________________ intervention
3. Intervention Examples:
a. Hire more help (increase capacity)
b. Pull resources from non-critical tasks (flexible resources)
c. Pay expedite fees (decrease variability)
d. Reduce scope (manage demand)
e. Find faster ways to complete critical tasks, etc…
20. Overview
1.
The game represents the effects of multitasking on task duration in any process.
2.
Players receive a batch of items, process that batch by working on all 3 tasks at
the same time, and then pass the batch to the next person in the process.
3.
A roll of a die will determine how much work each person gets done each day.
Setup
1. Organize into groups of 4 players.
2.
Each group assigns each player one of the following roles: Engineer, Document
Control, Approver I, and Approver II (for groups of 3, Approver I & Approver
II are the same player) arranged in the following sequence:
Engineer
Inbox
A
B
Document Control
Outbox
C
A
B
C
Inbox
A
B
Approver I
Outbox
C
A
B
C
Inbox
A
B
Approver II
Outbox
C
A
B
C
Inbox
A
B
Outbox
C
A
3.
Each player has 3 Inboxes and 3 Outboxes, for tasks A, B and C.
4.
The Engineer places 10 drawings (i.e. poker chips) in each inbox (Inbox A, Inbox
B and Inbox C) for a total of 30 drawings.
5.
Approver II plays and keeps track the of team’s progress on the Score Sheet.
B
C
21. Engineer
Inbox
A
B
Document Control
Outbox
C
A
B
C
Inbox
A
B
Approver I
Outbox
C
A
B
C
Inbox
A
B
Approver II
Outbox
C
A
B
C
Inbox
A
B
Outbox
C
A
B
How to Play
1.
On Day 1 the Engineer roles the die then moves that amount of drawings from his
Inboxes to his Outboxes by moving 1 at a time starting with Task A then B then C
then A then B etc... until the number rolled have been moved. For example, if he
rolled a 5, he would move 1 from Inbox A to Outbox A, then 1 from Inbox B to
Outbox B, then 1 from Inbox C to Outbox C, then 1 from Inbox A to Outbox A and
finally 1 from Inbox B to Outbox B for a total of 5 . On the Score Sheet Approver II
notes in the Day 1 row the number of drawings moved.
2.
If the Engineer doesn’t have a batch of 10 drawings in any of his Outboxes, he
continues his work on Day 2 by rolling the die then moving that amount of
drawings from his Inboxes to his Outboxes starting where he left off on the
previous day. In the example above, on Day 2 the Engineer would begin moving
the number rolled starting with Task C, then A then B, etc… Approver II notes in
the Day 2 row on the Score Sheet the number of drawings moved.
3.
When the Engineer has a batch of 10 drawings in any of his Outboxes (A, B or C),
then, and only then, he moves 1 stack of 10 drawings to Document Control’s
corresponding Inbox. For example, when he has 10 drawings in his Outbox A, he
moves them to Document Control’s Inbox A (i.e. not Inbox B or C).
4. On the same day Document Control rolls the die and moves that amount from his
Inboxes to his Outboxes. Approver II notes in the appropriate Day row the number
of drawings moved.
5.
If Document Control doesn’t have a batch of 10 drawings in any of his Outboxes,
play continues on the next day starting again with the Engineer.
Note: Each player plays, one at a time, in sequential order only, not in parallel
(i.e. No playing while others are rolling their die).
6.
When Document Control has a batch of 10 drawings in any of his Outboxes, then,
and only then, he moves 1 stack of 10 drawings to Approver I’s corresponding
Inbox.
7. On the same day Approver I rolls the die and moves that amount from her
Inboxes to her Outboxes. Approver II notes the number of drawings moved.
8.
If Approver I doesn’t have a batch of 10 drawings in any of his Outboxes, play
continues on the next day starting again with the Engineer, followed by Document
Control, then Approver I. Play continues until all 4 players are processing all the
drawings.
9.
When Approver II has a batch of 10 drawings in any of his Outboxes, then, and
only then, he notes it as a Completed Batch on the Score Sheet on the same day.
10. The game is over when all of 30 drawings, 3 batches of 10, have been completed.
11. Compare and contrast this game with Game 1 from the Queues & Batches training
and be prepared to discuss with everyone.
C
24. Notes:
1. How long did it take to get the 1st batch through the system?
2. How long did it take to get the last batch through the system?
3. How did you feel?
4. Let’s say there is a problem with drawing #2 that only Approver II can identify.
a. How long did it take to find out there was a problem (i.e. how long is the learning
delayed)?
b. How long would it take to get drawing #2 back through the process to where you
were assuming it had to go through the same process (i.e. Engineer
diagnose/correct, Document Control process, Approver I reviews, Approver II
reviews)?
5. How do these results compare to Game 1 of the Queues & Batches training?
a. What’s the difference between how the two games are played?
25. Key Takeaways
• Plan for constrained resources
• Don’t use safe task estimates, use 50/50
–
–
–
–
Safe = Slow
Just get it done
Don’t judge people on how long things take
Project Buffer allows for variability
• Don’t multitask
– Multitasking causes delays
– Know your priorities
PLAYBOOKHQ.co
@PLAYBOOKHQ