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Project Schedule Compression Techniques
What happens if we want to compress our schedule? Maybe it’s going to take a long time and we want to make it shorter – that’s where schedule compression techniques come into play.
Schedule compression is a technique that’s used to shorten or accelerate the schedule duration without reducing the project scope. We still want to deliver what we are delivering – that business value as part of our project – but we might have certain schedule constraints, imposed dates that we need to meet or other schedule objectives. So we need to compress that schedule.
There are two main compression techniques that you’ll see on the PMP exam and in the Project Management Body of Knowledge, and even in your project management career. Those two are “crashing” the schedule, which shortens the schedule duration by adding resources. That can be very costly as we’re adding more people or things. The other one we’re looking at is fast tracking, where activities or phases normally done in sequence are now performed in parallel or at the same time for at least a portion of their duration. That way we’re able to cut back on the time frame.
Let’s look at a few examples.
Crashing might involve approving over-time, adding resources, paying to expedite the delivery of activities on the critical path. Of course because of that crashing may result in increased risk, and certainly an increased cost.
As an example up the top here we’ve got Task 1, Task 2, Task 3 as our normal schedule with just one person assigned to each. But if we’re crashing this project schedule we’re adding resources to it, so now all of a sudden we’ve got a lot more resources there and we’re able to shorten the time of that task.
You have to be aware of the law of diminishing returns here, where sometimes adding more and more people -your return on that investment will get less and less over time. Sometimes adding more people isn’t the answer. But in this case, when we’re crashing a project we’re looking for that to be the answer to reduce our project schedule.
The other one is fast tracking, where we’re performing tasks in parallel. Again this might result in rework and an increased risk and cost, and it only works when activities can be overlapped to happen at the same time, to shorten the project duration on the critical path. We’re using the lead time, if there’s any lead time that we can take up we’re using that to perform those tasks in parallel. For example one, two, three in sequence but now one, two, three we’re performing some of these activities at the same time by fast tracking our project. Because we’re able to do that we don’t have to add more resources in this case, so the cost is a little bit less than if we were to crash the project with project resources. And that is the idea of schedule compression, crashing your schedule and fast tracking your schedule.
– David McLachlan