©2000 washington state university 1

©2000 Washington State University 1

Washington State UniversityEngineering Management Programhttp://www.cea.wsu.edu/engrmgt/

James R. Holt, Ph.D., PE.Associate Professor of Engineering ManagementDr Holt’s Home Page: http://www.vancouver.wsu.edu/fac/holt/

EM 530 Applications in Constraints Management Session 5

Intro to Critical Chain Project Management Continued

The beginning of the solution

http://www.cea.wsu.edu/engrmgt/









http://www.vancouver.wsu.edu/fac/holt/

©Washington State University 2

Administrative• Communication:

– In-Class Phone (360) 546-9060– WebCT Communications

•Chat Room 1 monitored

• PowerPoint Slides for this presentation are also available at:

• http:///www.vancouver.wsu.edu/fac/holt/em530/


The CCPM Solution to Project Management Scheduling

• Session 4 (Jun 5) was pretty depressing– Project Structure

– Task Variability

– Human Behavior (as a result of attempting to deal with structure and variability)

• Result, a single project planned for 70 days stretches to 160 days!

• Three 70 day projects exceed 350 days!


Painful Situation

3 Projects

3 Projects

Normal Distribution, 50% Task Estimate Confidence

Skewed Distribution, 50% Task Estimate Confidence

Skewed Distribution, 60% Task Estimate Confidence

75% Task Estimate Confidence


Add 75% Erroneous Reporting of Task Completions (Parkinson's Law)

Add Student Syndrome


Add Multi-Project, Shared Resource (Queues)

Add Multi-Tasking

50 150 250 350 450100 200 300 4000

Statistical Summary for PmSim Project Management Simulation

R. Furbeck 3/28/99

6e

8a

6d

6c

6a

6b

5

8b

9a

9b


We have Maxed Out!

• “We are caught in a vicious cycle which leads us to inflate our estimates and press for more people, just to see the completion dates of our projects slipping more and more into the future ...

• “... until the time to do the project becomes so long or the compromises on the content become so large that the clients tell us, “If that’s the case we’ll go elsewhere !” Eli Goldratt


We must improve or lose business and people

• “At that Stage, a very unsatisfactory equilibrium is reached:

• Lead times are long

• Visibility is lost

• The work environment is chaotic

• There is a loss of ability to make decisions

• Everything is done by pressure.” Eli Goldratt


Is it Possible?

• Some people have done it (See AGI Web)

• Example: Israeli Aircraft IndustriesF-16 Maintenance - Problem Resolution Flow

Time

0

20

40

60

80

100

120

140

160

1 2 3 4 5 6

Month

Le

ad

Tim

e (

da

ys)


What are the elements of the Solution?

• It makes know sense to intentionally schedule conflict.

• Prioritize the work

• Stagger the release of work (Job Shop Game)

• Communicate what is important to those who can make a difference

• How?


Multi Project Sim 9c

Tightest Scheduled Resource


Basic Stagger


Improvement helps a bitbut still Multi Tasking

First Project Median 169

Second Project Median 219(total time 323)

Third Project Median 235(total time 367)


We can Prioritize and try to do one at a time!


We are not good enough yet. We need protection

1 2 3 4 5 6 7 8 9 10

Completion Distribution

Due Date

Buffer

If we buffer our existing schedule,we just add more time!This is counter productive!


Take advantage of good statistics

1 2 3 4 5 6 7 8 9 10


Due Date

Buffer

Before: 85% Estimate


Due Date

Buffer

After: 50% Estimate

1 2 3 4 5 6 7 8 9 10

Notice, we areonly changing the schedule.Actual work is the same. If we finish early, we can capturethe advantage.


We can buffer the Critical Chain, but where else?


Due Date

Buffer

After: 50% Estimate

1 2 3 4 5 6

7 8 9 10


Add Resource Buffers


Due Date

Buffer

After: 50% Estimate

1 2 3 4 5 6

7 8 9 10

Make sure Resources are available to work when needed on the CriticalChain


Add Assembly (Feeder) Buffers


Due Date

Buffer

After: 50% Estimate

1 2 3 4 5 6

7 8 9

10 Make sure non-criticalside chains are de-coupledfrom the Critical Chain


Single Project Buffered

Critical Chain

Avoid Conflict

Sim 8 Resource Buffers

Feeder Buffers


Sim 8 Results

End of Buffer 98

Previous Median


Now let’s look at Multi Project

• We Schedule Each Project according to Critical Chain Project Management

• We stagger the projects according to a selected strategic drum (resources)

• We include a buffer between projects (on the drum)

• Estimate at 50%, Use Buffer Management


Stagger Projects w/Buffer

Buffer Between Projects Too


Result with 50% schedule and Buffers

First Project Median 96 90%@110

Expected

Second Project Median 180 90%@210

Expected

Third Project Median 216 90%@245

Expected

3 P ro jects

3 P ro jects

N orm al D istribu tion , 50% Task E stim ate C onfidence

S kewed D istribu tion, 50% Task E stim ate C onfidence

S kewed D istribu tion, 60% Task E stim ate C onfidence

75% Task E stim ate C onfidence


A dd 75% E rroneous R eporting o f Task C om ple tions (P arkinson 's Law)

A dd S tudent S yndrom e


A dd M ulti-P ro ject, S hared R esource (Q ueues)

A dd M ulti-Tasking

P rio ritize P ro jects,S chedu le D rum

U se C ritica l C hain S chedu les and B uffer M anagem ent,R educe E rroneous R eporting o f Task C om ple tions to 50%

50 150 250 350 450100 200 300 4000

Statistical Summary for PmSim Project Management Simulation

R. Furbeck 5/11/00

6e

8a

6d

6c

6a

6b

5

8b

9a

9b

9c

9d

9e

E lim inate B ad M ulti-Tasking


Bottom Line

• There is lots to gain

• Particularly in Multi Project Environments

• Single Projects 20% reduction

• Multi Projects 50% reduction

• Check out the simulators on your own.

©2000 washington state university 1

Business

date buffer

multi project sim

single project buffered

use buffer management

reduction multi projects

results end of buffer

day projects

previous median