Is Total Float All That ?
After five decades of Critical Path Method, we have all become used to the term Total Float, and it has made its way into how we interpret the Project Schedule, and how we actually manage our Projects. The question I dare to ask is this: is the Total Float value worthy of such prominence?
Just consider how versatile this single value is.
- We use Total Float to identify and trace the Critical Path of the Schedule. And since we interpret the Critical Path as the string of activities that is most vital to timely completion of downstream deadlines, we use Total Float to set our management priorities.
- We use Total Float to evaluate requests for Time Extensions that result from changed conditions or changed requirements (contractual).
- We use Total Float to speculate on the adequacy of project performance, as we estimate likely completion times.
- We use Total Float to give us an early warning (heads up) on performance slowdowns or sluggishness.
- We use Total Float in our evaluation of time-related claims that assert delay, acceleration, and even loss of productivity.
Not only have we put tremendous dependence on Total Float, we have put all of our eggs in this one basket. There are virtually no other indicators that we use in Project Time Management to rival our application of Total Float. Even the much-revered Earned Value is not seen as an alternative to Total Float, but rather as a complement, one providing a different perspective. Thus, even if Earned Value indicators suggest the presence of temporal deficiencies, the next step is to return to the CPM schedule and perform more precise analysis, including Total Float values.
Total Float is Not Without Its Limitations
All of the above would be scary enough, even if Total Float was this magic panacea. But the cold truth is that Total Float is burdened by shortcomings. Here are just a few:
- Total Float reports the numerical difference between two impossible extremes. Earliest Dates are unrealistically optimistic; the likelihood that all activities in a schedule will achieve their Earliest Dates defies reality. Alternatively, Latest Dates reflect an irresponsible postponement of work to an 11th Hour that no competent, prudent Project Manager would ever delay performance. Total Float measures the time gap between these two impossible extremes.
- Total Float is entirely unstable. Total Float changes with every shift in either Earliest Dates or Latest Dates. And given that Earliest Dates are unrealistically optimistic, they are forever being “missed” and, hence, in a constant state of change. Total Float is constantly changing, as well.
- Total Float can be tampered with … and typically is manipulated to some extent by every party that can get their hands on the schedule. Because the Critical Path (and its underlying Total Float) is at the heart of so many of the above uses of the Schedule, there is irresistible temptation to “alter” the logic to yield Total Float values more “favorable” to the manipulating party.
- Total Float is an ambiguous value. That is, there is less than overwhelming consensus on how to calculate Total Float. Some say it is the difference between Early Start and Late Start. Some say it is the difference between Early Finish and Late Finish. Some say it is the difference between Early Start and Late Finish. Some (including me) say it is the lesser of Start Total Float or Finish Total Float, per activity.
- Total Float exacerbates the Zero Sum Game mentality that infects every Construction Project and renders it dysfunctional. If the parties are not contesting over Money, they are almost certainly contesting over Total Float.
How the Owner Makes Matters Worse
As if all of the above weren’t bad enough, the Owner comes along with contractual nuances and requirements that only make matters worse. Without going into the full list (I have come up with over twenty Key Reasons Why Projects Fail), let me just mention a few here:
- Early Completion: Start with the common prohibition against the Contractor’s Baseline Schedule showing an early completion. To satisfy this requirement, the Schedule’s Critical Path must bear a Total Float value of zero. In other words, the Schedule’s longest path, the one that drives the contractual end dates, must not have any contingency whatsoever. Said mathematically, the Earliest Dates must be the same as the Latest Dates! At least with respect to the Schedule’s Critical Path activities, work is intentionally postponed to the last available moment! How rationale does that sound?
- Float Ownership: With respect to all other activities (that reside on Activity Paths that are not critical), whatever Total Float exists is contractually commandeered by the Owner. The political, financial, and practical implications of this edict cannot be overstated.
Picture yourself on the Interstate, driving at 60 miles per hour. For safety reasons, you leave six car lengths between you and the car ahead of you. Suddenly, someone spots that gap, and cuts in! So you fall back, again leaving the recommended six car-length gap. And again someone cuts in.
This is what happens when a Contractor builds some “wiggle room” into the Schedule, to provide a buffer and offset against the Unknowns of Life, the “surprises” that invariably afflict every Project. The Owner swoops in and claims the Total Float for itself!
- Float Sequestering: The Contractor’s only option, to counter Owner exploitation of its power, is to hide the Total Float. Aware of this, the Owner includes a clause that prohibits the sequestering of Total Float. Such clauses typically delineate the most common techniques for hiding float. But then, the Owner exempts itself (or its agents) from the bar on hiding Total Float. In the end, the Owner is free to bury Float and keep it from the Contractor; the Contractor cannot do the same in reverse.
- Schedule Integrity: Consistent with the previous item, Owners use the contract to further control and regulate what the Contractor puts into the Schedule. It dictates Level of Detail, use of software settings and which CPM logic controls are acceptable, ceilings on durations, and so forth. Yet, it exempts the Owner from these same regulations. These regulations, and exemptions, have a direct effect on Total Float values.
- Changes to Schedule: While the contract refers to it as the Contractor’s Schedule, the Owner insists on approving any changes to the Schedule. The Contractor is not free to alter the Schedule in any significant way without getting prior Owner permission. Total Float is used as the primary determinant as to whether such prior permission is required.
- Date Constraints: The Owner tightly controls the use of Date Constraints; contracts typically prohibit or greatly limit the number of Date Constraints found in the Schedule. Date Constraints have a sweeping and dramatic effect on Total Float values across the Schedule.
- Time Extensions: Virtually all contracts utilize Critical Paths (which are defined as activities with the least Total Float) to justify extensions of project completion deadlines. This puts extreme pressure on all parties to control the variables that influence where those Critical Paths lie.
- Progress Assessment: Similarly, Contracts typically require progress payment requests to be “validated” by the Schedule. This is a primary impetus for progress reporting shenanigans, even to the extent that progress is not reported on certain activities (thus, foregoing payment) in order to influence where the Critical Path(s) ultimately fall.
- Baseline Schedule: Almost without exception, contracts require the Contractor to submit its Baseline Schedule for review and approval to the Owner, before it can submit its first progress payment. The submittal, review, and approval process usually takes several weeks, if not a few months. Meanwhile, work has already begun on the project, during which time the Contractor is becoming aware of certain “realities” with respect to potential upcoming delays. The Schedule’s configuration is adjusted accordingly, including Total Float manipulation.
All of Our Eggs in a Basket with Holes
So, from the above, we see that (a) tremendous importance has been placed on Total Float and yet (b) Total Float contains many limitations and frailties. Worse, beyond Total Float, there don’t seem to be many alternatives methods for the primary uses of the Schedule: progress payments, time extensions, delay resolution, directing the work, or predicting outcomes. You might say that we have put all of our eggs in one basket, and that basket has quite a few holes!
Cognitive Project Management Suggests a Better Approach
After spending all of the above ink on knocking the current practices, this article would be remiss if it did not offer a better alternative. Cognitive Project Management has given much thought to the above concerns, and arrived at the following suggestions:
- Early Completion: Not just allow the Contractor to submit a Baseline Schedule that shows an Early Completion, instead actually require that the Baseline Schedule contain a time contingency of sufficient percentage that it provides a realistic buffer against the Unknowns that can be expected to afflict every project. Cognitive recommends a time contingency equivalent of at least 5% of the project length, but 10% would be better.
- Float Ownership: Cognitive believes that all Total Float should belong to the Contractor, not the Owner. This is the same policy all Owners adopt when it comes to money; why not the same with time? A Contractor bids $400,000 to do a job. It gets quotes from its subs to the tune of $375,000. The actual costs come in at $382,000. The contractor pockets the profit, $18,000.
Why doesn’t the same hold true for time? The Contractor bids twelve months to do a job. It gets commitments from its subs to accomplish the work in eleven months. That one month difference is the Contractor’s hedge against Unknowns. Why should the Owner take that Total Float for itself? It didn’t pay for it!
- Float Sequestering: The Owner should play by the same rules as are imposed on the Contractor. For example, Owner “Submittal Review/Approval” activities should not all have the same 20-day duration, regardless of complexity of submittal. Each Submittal Review activity should have a duration reflective of the amount of work required to perform the review. That might result in some reviews having five-day durations, while others might have 30-day reviews.
- Schedule Integrity: Instead of setting hard-and-fast parameters (maximums and minimums) on schedule elements, why not set performance objectives? For instance, instead of imposing a maximum Activity Duration, why not instead require that the Level of Detail be set such that the activities can be monitored and their progress assessed by visual inspection?
- Changes to Schedule: Allow the Contractor to truly own the Schedule, and thereby be allowed to change it at will, without prior Owner permission. Dispatchers at trucking companies do as much with their drivers. They give them a destination, a deadline, and goods to ship. The driver signs off on the assignment, and then the dispatcher trusts the driver to make responsible decisions along the route. The dispatcher does not micromanage!
- Date Constraints: The idea of having just one or two ultimate deadlines against which to monitor and assess project progress defies decades of Business Management experience and teaching. When it comes to money, we instinctively subdivide the Total Contract Amount into scores, if not hundreds, of Budget Line Items. We then track actual expenditures and compare them to budgetary estimates at the cost account level. Why don’t we do the same thing with temporal performance management? Why not subdivide the Schedule into scores if not hundreds of subordinate “builds,” and then track progress against each such project subcomponent? Cognitive Project Management uses MCPs (Momentum Checkpoints) for just this purpose.
- Time Extensions: Instead of using Total Float in conjunction with Time Impact Analyses (TIAs), why not use a Momentology formula that automatically determines the amount of extension (or retraction) of contractual deadlines based on Performance Intensity values. By taking Total Float out of the picture, a big reason why schedules are manipulated will have been eliminated.
- Progress Assessment: Likewise, use Performance Intensity, not Total Float (or Earned Value) to measure and report Work Progress.
- Baseline Schedule: Instead of waiting for Contract Award to kick off Schedule Development, why not require all bidders to submit a full-blown, detailed, Level 3 CPM Schedule along with their price proposal? This way, the Owner can have the ability to assess the likelihood that the bidder can deliver on its price and schedule proposals, by seeing that they have a credible and well-contemplated Project Execution Strategy. It can also more objectively compare the competitive proposals of the bidders.
And another huge benefit of this approach is that the Project Schedule will be in place on Day One! History has shown that 80% of all project delays take root during the first 20% of the project length. Those opening few months are critical to timely project completion. And that precisely is when the current practices have the Owner and Contractor batting the Schedule back and forth over the net. By requiring the full schedule with the bid proposal, the project will have a fully functional schedule on Day One.
Is Total Float All That?
I end this article where it began, with a question. Why do we put so much importance on Total Float? There are other, better, alternatives. Maybe it’s a case of ignorance; that most Owners, Construction Managers, Owner’s Representatives, Architects, and Engineers are simply unaware that there are alternatives.
Or maybe, just maybe, they like it the way it is. Maybe they prefer to continue under the false illusion that by controlling the Contractor they protect themselves.
I don’t know.
I just think that the current methods aren’t working all that well. With a 50%-70% failure rate across construction projects, the proof is not in the pudding. I, for one, am open to innovation. Are you?