Multiple float paths

Babu,

I believe blind looking at float paths value of float can be misleading, this might led you to focus on the wrong set of activities. A long duration activity with high duration variance on a longer duration float path might have more probability of becoming critical than an activity of shorter duration and lower duration variance.

Most contractors in the lack of probabilistic modeling in their CPM can pinpoint other paths with high probability of becoming critical using perception and common sense better than by creating a list of float paths all with different probabilities of becoming critical, very frequently a path of higher float they know it is the one to watch, as if a secret everyone knows.

Monte Carlo is very good at providing the required information on what activities you are to watch, better than the perception method that many times is better than the mere listing of paths by float without considering other risk factors.

Even when the determination of schedule probabilities will never be exact, if the approximation is reasonable the results will be of much value. A good probabilistic model will tell better in many occasions, as for example when an activity can slip into a bad weather season, the deterministic schedule will consider only one possibility and might miss a huge impact. Good modeling shall provide you with the tools to simulate the effect of seasonal weather on activities duration, this in combination with statistical modeling shall provide a better view than the deterministic schedule alone.

In addition to the above under resource leveling multiple critical paths can become too many to track individually. If you have 9 unlinked activities, each requiring the same resource for which you have only 3 available after resource leveling all will be in the critical path, but how many paths all of which will be critical will occur at the same time? This also adds to the equation of which activities are to watch. But wait, just add to the equation the fact that resource dependencies will not be fixed under true resource leveling that do not depends on soft links. But wait, we have just started, add to this conditional scheduling available in some advanced scheduling software that can toggle on and off complete paths based on user specified conditions. Again here Monte Carlo comes to the rescue like no other functionality.

Best regards,

Rafael

Hi Sunil,

My take on the option is that when you apply your multi-float filter it will show them in order, depending how many multi-float paths you require and the end activity.

I have absolutely no idea what your question means Sunil – EVERY SINGLE PATH in a properly constructed CPM schedule has float; so by definition there are ‘multiple float paths’ it is a simple fact of proper CPM scheduling.

In tight schedules there may be more then one critical path and if there are imposed date constraints there may be several paths with different negative float values.

I suggest you download our ‘Core papers’ on Float and Dynamic Scheduling and our White Paper (WP1043) on the definition of the Critical Path.  The papers are linked from our free Planning Resource page: http://www.mosaicprojects.com.au/Planning.html#Roles