Crashing refers to a particular variety of project schedule compression which is performed for the purposes of decreasing total period of time (also known as the total project schedule duration). The diminishing of the project duration typically take place after a careful and thorough analysis of all possible project duration minimization alternatives in which any and all methods to attain the maximum schedule duration for the least additional cost. There are a number of standard and typical approaches to attempting to crash a project schedule. One of the most commonly utilized methods of crashing a project schedule involves minimizing the schedule activity durations while, at the same time, increasing the assignment of resources on schedule activities. Crashing is something which can be utilized to attempt to get the most value out of a project assignment. Essentially, it boils down to an attempt to get the most productivity out of the least time and expense. Crashing is also similar to schedule compression as well as schedule fast tracking.
This term is defined in the 3rd and the 4th edition of the PMBOK.