Program or Project Evaluation and Review Technique (PERT)

1
Program or Project Evaluation and Review
Technique(PERT)
2

• What is PERT?
• A statistical method of assessing programs based
  on obtaining desired results
• A lexicographical ordering of tendencies that may
  have weighted desirable segments

3
How Can I Use It?

• PERT can be used to analyze data/characteristics
  etc. and increase the chances of obtaining a
  desired result
• - such as the best contractor making a bid
  for a construction project (not just based on
  reputation), based on characteristics you value
  most.
• - it is a mathematical screening process

4
PERTs 3 step process

• Consumer (you) have goals for a project, your
  options have random variables to fit the specific
  fields you have identified.
• Random variables (not really random)
  representing goals are converted to a probability
  distribution (usually Beta) when they are added
  together
• The weighted sum of the expected means is the
  aggregate expected mean of your goals selected,
  whose standard deviation is the square root of
  the sum of the variances of all the criteria for
  each.

5
Why do I want to use PERT?

• PERT is a system of analysis that can help make
  difficult choices.
• It is an unbiased system of reviewing options
  that are hand tailored for your specifications.
• It can be used as backup to substantiate
  decisions that were made and didnt quite meet
  expectations, or made someone very unhappy.
  (might help deter lawsuits)

6
What to be careful of when using PERT

• Up to date information
• Your random variables may change during a project
  
• Cut off points on acceptable data are one method
  of screening at an early stage, which may
  eliminate candidates that are really capable of
  providing what you desire.

7
CASE Jewelry Store Heist

• Youre a thief
• A jewelry store with a night patrol guard
• 50 minute window of opportunity

8
So little time but much to steal

• Exterior Alarm A
• Office Alarm B
• Office Safe C
• Jewelry Safe D
• Clean Jewelry E
• Exit - F
• Each A-F takes a certain amount of time, all
  steps cannot be achieved, use PERT to allocate
  time

9
Choose a path (O,ML,P)

• Activity Mean sd
• A 20 1.00
• B 7 .45
• C 7 .45
• D 14 .45
• E 4 0.00
• F 8 .45

10
Critical Path A-D-E-F

• Takes 48 minutes (by the mean)
• A,D,E,F sd Critical Path Variance(cpv)
• 1.45 0 .45 1.90
• sd of the cpv sqrt 1.9 1.378
• Z (50-48)/1.378 1.45
• 1.45 92.65 chance of avoiding detection

11
The Goal

• The Critical Path ADEF works
• But the goal is to steal (Critical Chain)
• the jewelry store is not cleaned out.
• What about the office? Activity Crashing

12
Results

• This case received high quality marks from
  students that were surveyed.
• Many students viewed 92.65 as acceptable risk,
  yet, understanding goals and maximizing effort
  are part of PERT