A project manager must be able to develop the project schedule. However, the skill of schedule development may not be enough as the demand to deliver the project sooner will require the project manager to adjust the schedule for reducing the overall project duration. For this purpose, the project manager will apply schedule compression techniques, viz. fast tracking and crashing.
If the stakeholders do not agree with the duration of the project schedule during initial schedule development, the project manager can conduct schedule compression. Sometimes schedule compression may happen while the project is ongoing due to changing needs or delays. Let’s look at the reasons for compressing the schedule.
Schedule compression reasons
There can be a non-exhaustive list of reasons for compressing the schedule during the initial schedule development. However, common reasons are as follows.
- An externally imposed deadline requires completion of the project sooner than later. For example, the deadline to submit some information to the government
- Lack of additional funding forces the project completion by the end of the fiscal year
- The project is part of the program which requires the deliverables from the project earlier so work can proceed on other projects
- A key stakeholder will be unavailable for an extended period urging an early finish of a part of the project work
- The project must be delivered before an operational contract expires, etc.
Now, here are some reasons for schedule compression while the project is ongoing.
- There is an urgency to compress the schedule because the work has progressed slower than expected. The slow progress may have been due to,
- the low skill level of project resources
- scarcity of resources
- a serious setback
- The original estimate was too aggressive and unrealistic
- There has been a change or an addition to the scope as the project progressed, etc.
So, one or more of these reasons may result in schedule compression.
Methods of schedule compression
There are two ways a schedule can be compressed; by fast tracking or crashing. Fast tracking usually results in increased risk while crashing mostly results in increased cost. There is a possibility that fast tracking increases costs. So let’s talk about these in detail. We will take the example of two activities A and B, that have a finish to start dependency.
In this method, the activity will start earlier than the originally planned start date. The work of two sequenced tasks will have an overlap. Overlapping refers to the parallel run of the two activities. So, when fast tracked, B will not wait for A to finish. Instead, it will start earlier and will run in parallel with A. The duration of each activity is unchanged, but the time it takes to complete the set of these activities is reduced.
Fast track the critical activities before considering the non-critical activities because fast tracking non-critical work will not produce any time saving as the deliverables and overall project is still taking the same amount of time. So the whole value of fast tracking is lost, and unnecessary risk is introduced in the project.
Activities that have the same resources working cannot be fast tracked against each other because a resource can work on only one task at one time.
Here is an example.
Activity A is ‘Design the Tower’ and activity B is ‘Construct the Tower’
Activity A has a finish-to-start relationship with activity B. The design, including reviews and refinement, will take three months to complete. The project manager, working with the project team and stakeholders, decided to begin construction one month earlier because the project must complete the tower sooner. Therefore, the team overlapped the two activities for one month.
What will happen if there are changes to the design as a result of the reviews? The changes may impact the construction work that has already started. So the risk of rework increases. If there is rework, then it will very likely increase the cost too.
Sometimes fast tracking may not be possible or desirable. In that case, the project manager can use crashing to get the desired results. Several methods can be used to crash the schedule and reduce the duration of the activities. For example,
- Add more resources, which can be both people and physical resources.
- Make resources work overtime
- Replace current resources with higher productivity ones
- Give an incentive to the seller for finishing the work earlier
All of the above options are bound to result in increased costs. To shorten the critical path, always crash the critical activities first. Once all possible crashing of critical activities is complete, then review the non-critical activities. If the critical path has shifted after the crashing of critical activities, non-critical activities may become critical. So these new critical activities can now be crashed, to further reduce the project duration.
Fast tracking or crashing?
The decision is not so easy. I suggest looking at several factors before making a decision. Here are a few important ones.
- Does the project budget has room to spend on crashing?
- How do stakeholders respond to additional work and project delay? Do stakeholders consider scope change as normal and an unavoidable part of work, or do they frown upon changes and delays?
- Are additional resources available? How long is the process of on-boarding the resources?
- Can we offer an incentive big enough that will entice the seller to finish the work faster?
Similarly, consider any other information that can help.
Stakeholders at an organization consider project end dates as fixed and are not willing to consider a delay. These stakeholders will accept higher risk and lower quality, but will not agree to extend the schedule. In this instance, fast tracking is always preferable.
Another organization considers quality as extremely important. Crashing would be a better choice then as fast tracking may impact quality.
So, projects may need to compress the schedule for various reasons. Both crashing and fast tracking methods are available. As discussed above, projects can consider several factors to decide which will be a better method for various sets of activities in the schedule.
Here are links to further readings on fast tracking and crashing techniques.