11-1 elc 347 project management week 12. 11-2 agenda integrative project –4 th part due –outline...
TRANSCRIPT
11-2
Agenda
• Integrative Project – 4th part due – Outline of deliverables (posted in WebCT)
• Quiz 2 Corrected– More effort wouldn’t hurt
• Today we will discuss Critical Chain Project Scheduling
11-3
Schedule for the final few Days
• Nov 28– Assignment 5 due
• Nov 30– IP part 5 due– Discussion on resource Leveling (Chap 12)
• Dec 7– IP part 6 Due (will be corrected and returned within 24 hours)– Quiz 3 Assigned (Chap 10, 11, 12, & 13)– Discussion on Project Evaluation and Control (chap 13)
• Dec 8 @ Midnight– Resubmission of IP part 1 – 5 deadline
• Dec 11 @ 10 AM– IP project (complete) due – Resubmission of Part 6 – IP project Presentation
• Dec 15 @ noon– Quiz 3 Due
• One less quiz and 2 less assignments then was identified in syllabus
11-4
Course Grading Rubric
Exams (3 @ 12% each) 36%
Assignments (5 @ 7% each) 35%
IP Project 19%
Pre-professional Conduct 10%
Total 100%
11-8
Theory of Constraints & Critical Chain Project Scheduling
A constraint limits system output.The Goal – Goldratt
TOC Methodology1. Identify the constraint2. Exploit the constraint3. Subordinate the system4. Elevate the constraint5. Repeat the process
11-10
VariationCommon Cause
Inherent in the systemSpecial Cause
Due to a special circumstance
Managers should• Understand the difference between the two
• Not adjust the process if variation is common cause
• Not include special cause variation in risk simulation
• Not aggregate discrete project risks
11-11
CCPM and the Causes of Project Delay
How safety is added to project activities
1. Individual activities overestimated
2. Project manager safety margin
3. Anticipating expected cuts from management
time
25%
50%
80%90%
Gaussian Distribution
11-12
Wasting Extra Safety Margin
1. The Student Syndromea. Immediate deadlinesb. Padded estimatesc. High demand
2. Failure to pass along positive variationa. Other tasksb. Overestimation penaltyc. Perfectionism
3. Multitasking4. Path Merging
11-14
Critical Chain Solutions
Central Limit Theorem
Standard deviation of the sum is less than the sum of the
standard deviations!
Aggregating risk leads to reduced risk
Activity durations estimated at 50% level
Buffer reapplied at project level– Goldratt rule of thumb (50%)– Newbold formula (2σ)
Feeder buffers for non-critical paths
n
11-16
CCPM Changes
Due dates & milestones eliminated
Realistic estimates – 50% level not 90%
“No blame” culture
Subcontractor deliveries & work scheduled ES
Non critical activities scheduled LS
Factor the effects of resource contention
Critical chain usually not the critical path
Solve resource conflicts with minimal disruption
11-20
Critical Chain Solutions
Bob
Feeder Buffer
Feeder Buffer
Feeder Buffer
ProjectBufferBob
Bob
Buffers protect constraints and prevent delays
11-22
Critical Chain Project Portfolios
Drum – system-wide constraint that sets the beat for the firm’s throughput
• Drum – person, department, policy, resource
• Capacity constraint buffer – safety margin between projects
• Drum buffer – extra safety before the constraint
11-23
Applying CCPM to Project Portfolios
1. Identify the drum
2. Exploit the druma. Prepare a schedule for each project
b. Determine priority for the drum
c. Create the drum schedule
3. Subordinate the project schedules (next slide)
4. Elevate the capacity of the drum
5. Go back to step 2
11-24
Subordinating Project Schedules
• Schedule projects based on drum
• Designate critical chain
• Insert capacity constraint buffers
• Resolve any conflicts
• Insert drum buffers so the constraint is not starved
11-26
CCPM Critiques
No milestones used
Not significantly different from PERT
Unproven at the portfolio level
Anecdotal support only
Incomplete solution
Overestimation of activity duration padding
Cultural changes unattainable
11-27
Problems on 373
• Assignment 5– Problems 1,2,3 4 & 5 on page 373 & 373
• Pert to CCPM– Figure total Duration– Take 50% activity duration
• Figure new total duration– Project buffer = 50%(old –new)
– If you have non critical path critical• Change to Late start • Feeder buffer is 50% of slack on non –critical path