Concept: When does a project need recovery? If you wait for a threshold like TSPI’s 1.10 to be breached, it’s too late. If indicators are noodling along, not too great, not too horrible, it might be too early. Raising the alarm would hurt your credibility.
To decide, you need more information. More than that, you need the right information.
Earned Schedule fills in the gap.
Practice: Let’s take an example.
Say that at the half-way point on a 10 month project, the Schedule Performance Index for time looks like this:
Sure, the project got off to a slow start, but it improved significantly. The SPIt is still climbing!
How does the Estimate at Complete for time look?
Given that the Planned Duration is 10 months, the duration estimates are not great, but they’re not too bad, either. Maybe, the project is not really in trouble, and there’s no justification for initiating recovery.
What does the To Complete Schedule Performance Index tell us?
The late start and nil SPIt throw off the first measurement. The other measurements seem to be hovering below the 1.10 threshold. Again, there’s no clear signal to start recovery.
So, what do you do?
Don’t ignore the situation and hope for the best. Don’t flip a coin. Get more information.
Another measurement from Earned Schedule helps: the Window of Opportunity.
Based on current performance, the Window of Opportunity for recovery has sunk to .132.
To put that into perspective, if all the remaining time were available, the Window would be 1.000. If no remaining time were available, it would be 0.000. So, it’s possible, but the Window is small.
You might think, “Wait, the project is only 60% complete. Surely, recovery is possible with a full four months to go!”
Not so!
Walt Lipke’s research has shown that once the TSPI hits 1.10, recovery is very unlikely. The math behind the Window of Opportunity is tied directly to that break point. [1]
The Window measures the time available before the threshold is breached. So, it’s not four months of runway. It’s less than 15% of the remaining timeline. The percentage is informative, but a picture is better.
For the picture, convert percentage to number of days. At .132, the number of days before hitting the threshold is 16.2. Not four months; instead, less than one month. At the current level of performance, the project will be unrecoverable in less than a month.
Note the trends. The Window narrows after March—there’s less and less time available for recovery. Simultaneously, there’s a growing disparity between the time before 1.1 and the time before project end. That fosters over-confidence because it appears more time is available than there actually is available.
The trends support the call for recovery.
Admittedly, that call is subjective, as there’s no threshold breach. With subjectivity comes vulnerability to Kahneman’s “cognitive bias” and Flyvbjerg’s “strategic misrepresentation”.
So, as a rule-of-thumb, err on the side of caution, and start remediation early, rather than too late.
Here are the Pros and Cons for Window of Opportunity:
Pro:
- Quantitative metrics resist cognitive bias and strategic misrepresentation.
- The Window is derived mathematically from TSPI, inheriting its theoretical and empirical support.
- Percentage of time is easily converted into number of days until 1.1 is breached.
Con:
- How much “room” is enough to recover? Subjectivity creeps back into the metric.
[1] The math behind the Window is challenging. But, at a high level, you find the fraction of plan that will be achieved at 1.1. It’s the ratio between the planned time as of 1.1 and the likely time (given current SPIt) as of 1.1. Then, you subtract the fraction already earned. For details, click here.
|
