Insights

Modeling Float-Use Risk in Schedule Risk Analysis

Use of float and its influence in the likelihood of completion has been overlooked in Monte Carlo schedule modeling, leading to exceedingly optimistic probabilities of completion. This Keynote illustrates how the Graphical Path Method (GPM), by modeling the risk of float use in schedule risk analysis, assists schedulers in more accurately predicting probable project finish dates.

Modeling the Risk of Speculative Float Use

• (A) Use a uniform distribution: use from 0% to 100% on every activity with a likelihood of 100%
• (B) Pace the likelihood of float use: use free float in the first 20% of project duration, use 50% total float up to 67% of project duration, and use free float in the last 33% of project duration
• (C) 100% total-float use for every activity yields the pessimistic completion risk curve
• (D) Limiting total float use in Monte Carlo modeling to safe float yields the SAFE project finish risk curve and a more reliable forecast of probable project finish dates

This innovative GPM scheduling principle allows schedulers to model the risk of float use in schedule risk assessment, leading to a more reliable forecast of probable project finish dates.