Probability of Program Success P(s)
Assessing Schedule Risk is One Step
Probability of Success P(s)
Assesses a project’s
performance using 4 simple
It is the Planning metric that
can be assessed using two
methods deployed by Lewis &
Monte Carlo Simulation
The Data Elements of a Project are Random Variables
Cost, Schedule, Technical Performance and Risk
Each is drawn from a
The shape of this
distribution has direct
impact on the
confidence of the
their outcomes is
what a Monte Carlo
The Schedule Assessment Process
Task with no successors
Tasks with no
Must Finish On
Finish No Later Than
Must Start On
Start No Later Than
completing on or
before a planned
Schedule Health Schedule Risk
Every Manager Should Know…
When will this project finish?
Is the project’s schedule realistic and achievable?
What will it cost when we are done?
How is the project performing against its plan?
What deliverables are slipping?
How are we going to get the deliverables back on schedule?
What does past performance say about the future performance?
What is the impact on the schedule of any change requests?
Is there enough schedule slack and reserve to cover the risk?
Is there enough management reserve to cover any overrun?
Where is the risk in the schedule?
How can we get the work done sooner to reduce risk?
How can we recover from any foreseen delays?
How can we work around a problem?
Monte Carlo Risk analysis starts with a credible
schedule and defines the probabilistic behavior of
each activities and how it drives the deliverables
The Risk+ tool sets the upper and lower bounds of the possible durations
Date: 2/25/2009 3:34:12 PM
Unique ID: 30
Name: Final Testing
Completion Std Deviation: 5.51d
95% Confidence Interval: 0.62d
Each bar represents 2d
Tue 2/11/03Mon 1/20/03 Mon 3/3/03
0.16 Completion Probability Table
Prob ProbDate Date
0.05 Wed 1/29/03
0.10 Fri 1/31/03
0.15 Tue 2/4/03
0.20 Wed 2/5/03
0.25 Wed 2/5/03
0.30 Thu 2/6/03
0.35 Fri 2/7/03
0.40 Mon 2/10/03
0.45 Mon 2/10/03
0.50 Tue 2/11/03
0.55 Wed 2/12/03
0.60 Thu 2/13/03
0.65 Fri 2/14/03
0.70 Fri 2/14/03
0.75 Mon 2/17/03
0.80 Tue 2/18/03
0.85 Wed 2/19/03
0.90 Thu 2/20/03
0.95 Tue 2/25/03
1.00 Mon 3/3/03
The output of Risk+ is a Probability Distribution Function and a
Cumulative Distribution of all the possible dates that “watched”
activity could take.
This shows the Confidence in the target date – 2/10/3
It shows 40% chance of completely on or before 2/10/03
A confidence metric that the project will complete
on or before the planned date
Measures of the integrity of the activity network
Overly constrained plan
Activities with no dependencies
Visibility into the Probability of Success from a
schedule point of view