Over the last few years I have seen a lot of compliance issues arise from the "required float threshold" in scheduling. For the schedulers, it is pretty clear why lower float enables you to see issues in a schedule quickly, validate the critical path, ensure everyone knows when work needs to happen, ensure impacts are accounted for, and validate the duration of the project, but the industry documentation does not provide a clear definition of a threshold, nor a real reason why this is important.
For instance the GAO GAO-16-89G (pg 94-95) states: Given that float is directly related to the logical sequencing of activities and indicates schedule flexibility, management and auditors will question what constitutes a reasonable amount of float for a particular schedule. Activities' float differs by status period, given the logical sequence of activities in the network and the program's remaining duration. Therefore, management should not adhere solely to a target float value (for example, maximum 2 working periods) or specific float measure (for example, 10 percent of program duration). Large amounts of float may be justified, given an activity's place in the flow of work. For example, landscaping or paving in a construction project may slip many more months than pipefitting. Likewise, nonessential activities in a 2-year project may have far more float available than the same activities in a 6-month project.
From a cost perspective, there is a lot of concerns on the PMB as it relates to the monthly / yearly budget, performance, and funding. For discussion, I propose the following questions (and yes I am getting a lot of challenges on this from the contractors, so more industry guidance is helpful!!) :
1) Why is high float an issue? From the government prospective, from the owner, from the prime, from the contractor, from the subcontractor?
2) Why can't we use float for risk? or should we?
3) What is the value of buffer activities, or extra milestones? - what is the issue with these activities to just reduce Float?
4) Should there be an industry maximum float threshold?
5) Are there any studies that argue one way or the other?
6) Is there a value in long lead activities or accelerated procurement with buffer activities and material storage?
Michael Marcell EVP PSP