total float erosion reporting

Reports on total float trends make sense only if there is Must finish date in the schedule.
In other case trends of forecasted completion dates are most useful for project performance analysis.
Spider Project shows trends of all project parameters from the project start to the current date. We usually do not apply Must Finish constraints in the schedule but define target dates and costs for risk analysis. Trends of probabilities to meet project tartgets are best performance indicators.
Best Regards,
Vladimir

Hi Vladimir,

If throughout the project you are consistently behind programme on near-critical activities, they will eventually eventually affect the forecast completion.
Trending total float allows you to see this happening before forecast completion is affected
There is a causal relationship between erosion of total float and decreasing probability of meeting forecast completion date

I agree that what matters most is forecast completion, but understanding total float trends is also a valuable performance indicator.

We will also be reporting trend of probabilities, but this is affected by both risk and progress. Float doesn’t look at risk but tells you more about how the project is activities and that the right activities are being progressed.

Hi Gary,
total float trends will not show anything if there are Must dates in the schedule, that we try to avoid.
If for some reason the milestone will be delayed total float trend of activities preceding this milestone may look positive despite the poor performance on this group of works.
That is why we suggest to look what happens with the forecasted completion dates of major project phases.

You are right that probability trends depend both on performance and on risks. That is why we consider them as best performance indicators because they provide us with integrated performance measurement data.

Hi Gary,

can you please explain to me in simpler terms the relevance of Total Float Erosion and how it serves as a tool to monitor/control the project!

Thank you,
Rami

Rami,

As a project progresses, some activities will be completed early, thereby creating more total float for it’s successors. Some will be late, thereby eroding the total float for it’s successors.
If enough (non-critical) activities are late, eventually their successors will become critical and impact on the forecast completion.

Unless you look at errosion of total float and/or probability of achieving forecast completion date, you won’t notice this process happening until the forecast completion date is affected, by which time it may be too late to do anything about it.

If on the other hand you report with each update the total number of activities with, say less than 10 days total float (or one of the other methods of tracking float erosion I mentioned in my first post), you can easily see a trend developing whereby more activities are becoming near critical, and will soon delay the project if this trend is not addressed.

You can get something similar by just looking at the number of activities which are late vs baseline or previous month’s forecast, but many of these activities will have enough total float that a week’s delay will have no effect on the chances of completing on time. And some activities will be completed on time or even early, but had so little total float that their successors still present a risk of delay.