Using Multi-Path Residency to Accelerate a Schedule

At first, this will seem like a rather technical discussion. But it has real-world significance, especially when a Scheduler is asked to recommend where to “blitz” a schedule.  Let’s get into it.

Some Extra Men Have Come Available: Where Can They Do the Most Good?

As a Scheduler, this is a question that you just love to hear. In all honesty, we don’t hear questions like this often enough! The truth is that the Project Schedule is rich with valuable information that can help the Project Team more efficiently and more effectively execution the Work of the project. But how might we answer the posed question? On what basis should we advise as to where to deploy the extra labor resources?

Assuming a Temporal Interest in Our Answer

The following discussion assumes that the question was aimed at finding out how the deployment of additional labor forces might lead toward an earlier completion of one or more Project Execution Commitments (firm deadlines). That is, it is assumed that we are concerned with temporal outcomes, as opposed to consequences related to cost, risk, safety, or other important considerations.

Biggest Bang For the Buck

An familiar expression is that we want to determine where we will gain the biggest bank for the buck, the greatest temporal improvement in exchange for the deployment of additional resources. So, what are some possible bases for answering this question?

  • Least Float Path: An obvious answer – and the one most often chosen – is to assign the additional labor resources to any of the Activities having the least Total Float in the Schedule. But that might not be the best choice, as we shall soon discover.
  • Longest Path: Another equally-common choice is to apply the resources to any of the Activities residing along the longest path in the Schedule. For the same reasons, however, this might not be the best choice.
  • Largest Duration: Another intuitive answer might be to apply the resources to Activities that have very large durations. The presumption here is that if we double the labor of such Activities, we cut their duration in half.
  • Most Successors: A smaller percent of responses might zero in on Activities that have the largest number of immediately-succeeding (downstream) Activities tied to them. The theory here is that if we can complete the predecessor sooner, then all of those immediately-dependent Activities can start that much sooner!
  • Nearer the Deadline: Finally there is an argument for applying the additional resources to Activities that are closest to an impending Milestone. The nearer an Activity is to a Milestone, the more critical is its timely completion (for there is less time to “make up” for any slippage of such an Activity).

So Which Answer is Right? Which is the Best Answer?

There may be other valid options, but these are some that immediately come to mind. But which, of these, is the best option? Of course the answer to that question is a matter of opinion. And it is unlikely that the following opinion will convince those holding different views.

The point of raising the question in the first place was not so much to find the right or best answer, but rather to raise your awareness of a little-known attribute of all Critical Path Method schedules, and of the vast majority of Activities within those schedules: the typically Activities reside simultaneously on multiple paths!

In most CPM Schedules, Activity Paths crisscross and intersect in such convoluted ways that the majority of Activities reside on more than one Activity Path. ICS-Research defines an Activity Path as a series of Activities that span between a Start Milestone and a Finish Milestone.

Introducing Multi-Path Analysis as a Way to Answer the Question

ICS-Research has developed an innovative process to answer this question. And it really works! Multi-Path Analysis consistently identifies the best place (on which Activities) to deploy additional resources in order to provide the overall Schedule with the most temporal benefit. In fact, the Multi-Path Analysis option has proved more effective than even Least Total Float or Longest Path options in this regard.

If you have the stomach for a highly technical paper, I invite you to read ICS-White Paper WPA-MF-28, entitled, “Schedule Acceleration Using Free Float and Multi-Path Analysis.” This paper fully explains the principles behind Multi-Path Residency as it conducts a detailed comparison of the Multi-Path Analysis with the above five other options: Least Total Float, Longest Path, Largest Duration, Most Immediate Successors, and Nearest the Deadline.

The concept behind Multi-Path Analysis makes good common sense. If you are comparing two Activities, one that resides on only one Path, and another than resides one multiple Paths simultaneously, if we improve the performance of the latter we positively impact multiple Paths in one felled swoop.

If you would like to learn more about Multi-Path Residency, I strongly encourage you to read the referenced White Paper.




2 Responses to Using Multi-Path Residency to Accelerate a Schedule

  1. Zach Reed says:

    Indeed, another thorough analysis about how to better analyze a schedule. Though instinctively one leans toward adding resources to the longest path or the path with the least total float, intuitively it makes sense to consider activities on the most paths. I hope to have an opportunity to test out this process on one of my projects.

  2. Sue Backiel says:

    A very interesting topic. The White Paper was excellent in demonstrating the benefits and drawbacks of the different approaches of schedule acceleration. I will keep this White Paper handy and use as reference in the future.

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