Question

In project management you can crash activities. How do you calculate the shortest delivery time and project cost.

thanks in advance.

Answer 1

There are two aspects of crashing a project - optimal crashing and maximum crashing. The former represents the least cost approach to crashing and the later ignores the cost aspects and only focus on the maximum possible crash.

When it comes to the maximum possible crashing, we should first look at the available project paths. We crash activities only on the critical path(s) (i.e. the paths with the longest duration) to crash the project. If multiple critical paths are there (or emerges at a stage of crashing), all of them has to be crashed simultaneously by selecting appropriate activities. This process will eventually lead to a point where we will find one or more critical paths on which every activity has been crashed to their individual crashing limits. This is the maximum possible crash and is often known as the crash point of a project.

If we are interested in finding the optimum crushing point, additional complications suffice. Note that when we crash a project, there are certain monetary benefits (e.g. in terms of reduced indirect cost or in terms of lesser penalty or higher incentives from the customer). But the direct cost increasing due to additional resources being employed in crashing the activities. The decision-maker is supposed to find the point at which the total cost (which is the total of the normal direct cost, additional crashing cost, and indirect cost of the project) is the minimum. This point is known as the optimal crashing point for the project.