As a critic of sharing, Hess understood that he would provoke criticism. He has. Numerous CPM and contracting experts pronounced his critique of shared resources as misguided, lawyerly posturing. ">Fredric L. Plotnick, a Philadelphia-based CPM consultant, compares the idea of single-party float ownership to saying someone owns "the light that's in the air."

 

MANGINELLI

">Trauner Consulting Services

"There's a premise [in Hess' article] that float is put into the schedule purposely for a reason, and I believe that was a false premise and that that misunderstanding of float allows for the entire discussion to take a wrong turn when critiquing who should own it," according to Manginelli.

Manginelli, who defines float as the difference in workdays between the early and late dates of an activity, made his arguments in an article in the summer 2011 issue of the American College of Construction Lawyers' Journal. Manginelli and his colleagues Theodore J. Trauner Jr. and Brian Furniss wrote that float is nothing more or less than "a dynamic arithmetic calculation" that is "based on the forward and backward pass of the CPM algorithm."

"The schedule logic and durations dictate what float exists for a specific activity," they write, and it varies at different times during the project.

The result of the interrelationships among activity durations, logic and constraints, float isn't built into schedules or allocated to certain activities as a cushion against unexpected delays. The idea that float can be sequestered for a particular use—hidden or squirreled away so that the owner can't see it or find out about it—can be done only by expanding the time designated for an activity.

"Any gamesmanship up front, if even possible, will likely yield unintended consequences," wrote Manginelli and his co-authors. "This game has a large downside for the contractor; it essentially makes delays caused by the owner" hard or impossible to see and document, they write.

Float may no longer be as relevant as it once was. With the advances in CPM software and its enhanced scheduling features, the critical path may comprise activities with many different float values, say Manginelli and his co-writers.

"In the past, most project managers were conditioned to look at the float values and draw conclusions based solely on those." That approach now may be meaningless because float may have no relationship at all to what is critical or to what may cause a delay to a project.

On projects for the California Dept. of Transportation, the department and the contractor own any float either party creates if it completes a task ahead of schedule. This isn't quite the same type of sharing that some who call for float-sharing have in mind. Nevertheless, "This has been a good thing for our members and has minimized disputes," says a spokeswoman for the Associated General Contractors of California.

The agency's rules and contracts designate that Caltrans may accumulate department-owned float by early review of a submittal that saves time. Overall, the agency is fair on delay issues and float, says a construction manager who is familiar with Caltrans' schedule specification revision committee.

Too Much Complexity by Caltrans?

But, over the years, Caltrans has modified its specifications related to contract time as the complexity and constraints placed on projects have increased. For example, Caltrans specifies that contractors must use [Oracle's] Primavera P-6 chart for a $3-million paving job that could involve only three or four activities. "You could do the whole thing with an Excel Spreadsheet bar chart" for less, says the construction manager.

One sticking point is the delays related to utilities. Under a special provision that has been introduced into Caltrans contracts in the last 12 months, an excusable delay could be caused by a third party who has right-of-way agreements with Caltrans, even though the contractor has no control over the third party. "It shouldn't be the contractor's burden," says the construction manager.

"Say, for example, we're building a bridge and draft falsework drawings," he explains. "They could start nit-picking at it, and even if they give us added time, they can also claim the utilities weren't moved in time."

An even more energetic criticism comes from William A. Manginelli, president of , Philadelphia. Rather than being a static resource subject to control by the companies on a project, says Manginelli, float is a mathematically determined value that changes during a project and requires much tedious effort for a company to manipulate.