Austin F

How to Successfully Crash a Project

Est. Reading Time: 3 minutes

Anticipating problems is a large part of what it takes to be a Project Manager. Every now and again, a problem is big enough that you’ll have to crash the project (add additional resources to meet the deadline). It isn’t something that should be done lightly, as its effects can reach beyond the project team to the entire company and even other clients. My next post will be about when it’s appropriate to crash a project, but in the mean time, let’s focus on how to do it.

If you read my post a few months back about Finding the Critical Path, then you already know which activities will affect the project deadline. When you want to crash a project, you must add resources to one of the activities on the critical path. Your focus is to reduce the number in the duration cell. Keep in mind that duration refers to real-time to completion of that activity and not working hours. Working hours may actually go up when you crash a project because new resources will need time to get up to speed.

First, identify the activity you want to crash. Focus on doing one at a time, and I’ll tell you why later.

Look for:

  • A larger activity that can support more resources
  • A fairly common activity that doesn’t require high specialization
  • A task that can be completed modularly

Once you’ve selected the task, figure out which resources will fit and assign them. Make sure you have open communication with your current team to make them aware of the change and why it’s happening. You especially want to give a heads up to the person whose activity is being crashed to give them a chance to prepare assignments for the new members.

Now you must come up with a new duration number for your critical path chart. Let’s start with the example from my earlier article:


Say we crashed Activity G, so instead of taking 60 hours (or 7.5 days to complete), it will take 30 hours. Let’s plug in the new number and rework the chart a little. You’ll have to redo all the late start numbers to make sure they match up. cpm-crashed We’ve successfully crashed the project, so the time to completion went from 244 hours to 214 hours (we shaved off just under 4 working days). But now we see that we have a new critical path. Activity G is no longer on the path, but Activity H is now. That is why we crash one activity at a time, there is a new critical path. If we tried crashing multiple activities at once, we might be crashing activities that are no longer critical, and thus there would be no impact on the overall project deadline. Similarly, Activity H may now be a prime candidate for crashing, whereas before, it didn’t matter.