Fast Tracking Vs Crashing: Key Techniques for Project Schedule Compression


There are two ways to compress the Project Schedule (Time) without reducing the scope of the project:

  1. Crashing

  2. Fast-Tracking


Crashing involves including resources for a particular project activity. This is done so that the project can be completed seamlessly and quickly, but this method tends to be costly.


Fast-Tracking involves changing the string of activities so that some of the activities are performed simultaneously. It increases the risks involved as it ignores the discretionary dependencies and performs additional activities parallelly. It does not always increase the cost to the Project.

Project Schedule Compression

It involves compressing or shortening the Project Schedule without reducing the project scope in order to meet the schedule constraints imposed by the customer or sponsor. It is not always possible to compress the schedule without an increase in the project cost.

It is used:

  • When the project has unrealistic time-frame or schedule end dates.

  • During Integrated Change Control process to analyze the impacts on the Project Schedule (Time), Cost, Scope, Risk, Resources, Quality and Customer Satisfaction.

  • During project planning, when the management or the customer requires a completion date that cannot be met.

  • During executing, when the project manager needs to bring back the project in line with the schedule baseline or for approved change requests.

A Project Manager must have the professional responsibility to make sure the project is achievable by properly planning it. He/she must use the schedule compression technique to determine the desired completion date that can be met; if not, what can be changed to meet the imposed schedule end dates or unrealistic time frame?

If you have negative project float (the estimated completion date is after the desired completion date), would your first choice be to tell the customer the date could not be met and to ask for more time? No, the first choice would be to analyze what could be done to avoid negative project float by compressing the project schedule.

Many Project Managers use the Project Schedule Network Diagram to manage the day-to-day operations of the project and to make adjustments when changes occur in the project schedule.

Two Techniques of shortening project duration

Neither Fast Tracking or Crashing techniques always succeed in bringing back the project in line with the Schedule Baseline.

Fast Tracking

It involves compressing the Project Schedule by rearranging the Project Schedule Network Diagram and changing the relationship of activities on the critical path from Finish-to-Start to Start-to-Start or by adding lead time to downstream activities to perform activities in parallel that would normally be done in sequence.

Fast Tracking Diagram

Example: Changing the relationship between "Paint Rooms" and "Install Carpet" activities by adding lead time to "Install Carpet" Activity in Project Schedule Network Diagram.

  • Before the change: Rooms must be painted before Carpets are installed.

  • After the change: With the added Lead Time, Carpet can be installed just hours after a room is painted.

  1. It saves time but more often it results in rework, it increases Project Cost and Risk, It also requires more attention to communication among the team to do the work.

  2. It overlaps the Phases of the Project; i.e., Phase 2 can start before Phase 1 is completed.

  3. Interdependencies between the Phases must be managed properly to avoid Risk and Rework.

  4. Uses the already planned resources.

  5. It involves overloading the resources if the same resources are used on an activity and its immediate successive activities. Resources may find themselves working for more than sixteen hours per day.


It involves adding more or adjusting physical and human resources to the Critical Path Activities to shorten the project duration without changing the Original Project Scope.

Crashing Diagram

  1. It may save and reduce project schedule duration, but it always results in increased costs due to increase in the number of resources.

  2. It may involve resources like weekend work, over time to meet the Project Timeline Constraints. This results in team burnout.

  3. It may involve increasing the Risk.

  4. It may also involve using the resources from non-critical path activities, but you must be careful that this may cause the abandoned activities to quietly go critical.

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Fast Tracking Vs Crashing: How are they different?

Fast Tracking Vs Crashing

Why and when to use these techniques?

Scenarios to use Crashing:

1. You are the Project Manager for XYZ Project. You realize that the Project cannot be completed within 5 months. You decide to get management's approval to add more resources to complete the project on time, without changing the Scope of the Project. The technique used is?

Answer: Crashing

2. The Cost Performance Index is 0.75 (Over Budget) and Schedule Performance Index is 1.85 (Ahead of Schedule) for your Project. What could be the possible reason?

Answer: The project was crashed to decrease the duration in anticipation of delay in the project. Crashing of project results in a decreased duration and increased costs.

3. The Performance Index of Cost is 1.5 and Schedule is 0.5 for your project. What is your plan of action?

Answer: CPI is greater than 1 (Under Budget) and SPI is less than 1 (Behind Schedule). The preferred action to be taken is to crash the project to bring it back on the schedule. Crashing may increase the costs to the Project. Cost is not a major issue because the CPI of the Project is greater than 1.

4. The Critical path of the project is 23 weeks. If the management wishes to finish the project within 18 weeks. What is the impact on the term of the critical path?

Answer: If the management wishes to complete the project within 18 weeks, then the project slack will be- 18-23 = -5  weeks. The project slack compares the critical path with an imposed date by the management, if the project slack is negative, then you have an option to either perform crashing or fast-track to ensure that the project is completed on time as desired by the management. So, there will not be any changes in the critical path.

5. Your Customer wants some change to be implemented in the project scope. You determine that the change in scope will not impact the project schedule, but it will increase the cost of the project by $50,000. What should you do first?

Answer: It is not recommended that you use Crashing or Fast-Tracking, because the Project Schedule is not impacted by the change. So, discuss with your project sponsor regarding the increase in the project costs.

6. The CPI of a Project is 0.8 (Over Budget) and you have a limited budget. You are planning to procure a product from the supplier. In this situation, what should you do?

Answer: Find ways to decrease costs since CPI is 0.8, the project is over-budget. You cannot try to crash the project as it increases the costs further.

7. Crashing helps to bring the project back on schedule if it is delayed. What should you do?

Answer: Crashing should be done on the activities of the critical path of the project if you want to reduce the duration of the project.

8. The customer has given you a project to construct a building. The project is delayed due to some unforeseen incidents and the customer has demanded that you pay a penalty of $50,000, if you are not able to complete the project on time. To avoid the penalty, you planned to work overtime, add more human resources and rent physical resources to complete the project on time. This is an example of:

Answer: Crashing, as you have brought some extra resources to bring the project on track.

Explore Key Principles of Resource Management

9. The activities A, B, and D are on the critical path and must be performed in that sequence. Assuming activity C does not lie on the critical path and cost is important, in which sequence should be crashing of activities be planned?

  • Normal Time (Weeks): A=4, B=3, C=5, D=5

  • Crash Time (Weeks): A=2, B-2, C=4, D=3

  • Normal Cost(Dollars): A=10, B=20, C=14, D=25

  • Crash Cost(Dollars): A=11, B=22, C=16, D=27

Answer: The sequence for crashing activities should be A, D, B. Activity C is not on the critical path and does not really need to be crashed. If you want to crash the activities by cost in ascending order, then you come up with this sequence- A, B, D.

  • Activity A: 4-2= 2 weeks crash --> (11-10) 1K$ Increase in Cost--> 0.5K per week

  • Activity B: 3-2= 1 week crash ---> (22-20) 2K$ Increase in Cost--> 2K per week

  • Activity D: 5-3= 2 week crash ---> (27-25) 2K$ Increase in Cost--> 1K per week

Choose the Activity A first, because it provides you with the best crashing time at the lowest cost. Then you chose Activity D that provides you with the most crash time at the lowest cost. Finally, choose the Activity B.

10. You are behind schedule by 3 months and you are under-budget by $ 70,000. What is your best course of action?

Answer: Since the project is delayed and you are under budget, you have enough funds; and so, you can crash the project to make up for the delay in the project schedule.

11. There are five tasks (A, B, C, D, E) that need to be completed sequentially in your project. The Project is delayed and has a Negative Project Float of 3 Months. To avoid Penalty, which of the following tasks should be crashed to bring the project back on Schedule?

Please refer to the table given below showing additional expenses that will be incurred when each task is crashed:

Additional Expenses Table

Answer: Project Schedule has to be crashed to avoid negative float of 3 months. So, task B and C will provide Crash Savings (2+1= 3 months) and an additional minimum Crash Cost expenses ($100+$50=$150), or task E will provide Crash Savings (3 Months) and an additional minimum Crash Cost expense ($150). So, select the option to either crash the Tasks (B&C) or task E.

12. The Project Schedule Network Diagram for your Project is as shown in the figure below (Duration is in days):

Project Schedule Network Diagram

If Customer wants to complete this project within 14 days, what would be the project float?


Start→ Task 1→ Task 2→ Task 6→ End: 1+6+3+4=14 Days

Start→ Task 3→ Task 4→ Task 8→ End: 3+2+5+6=16 Days

Start→ Task 5→ Task 7→ Task 8 → End: 4+3+5+6=18 Days -> This has Critical Path.

The duration on the critical path for the Project is 18 days.  If the project has to be completed within 14 days, the project float is - 4 days; i.e., 14 - 18. So, Project Manager must either have the option to perform fast-track or crash the project schedule, if the project has a negative project float; i.e., -4 days)

13. The project XYZ has a project float of -3 months. Which activity or activities in the below table would you crash to save 3 months on the project XYZ. How much would it cost to crash this project XYZ?

Cost of Crashing Project_1

Answer: The Option to save 3 months are:

Cost of Crashing Project_2

Crashing Activities A and C is the least expensive option- only $5,000. If you have negative project float in your Project, it means that the project is not going to meet its customer imposed deliverable date.

Scenarios to use Fast-Tracking:

1. The Project is behind Schedule. The customer has agreed on a revised delivery date for Project from Project Manager but the customer has not accepted an increase in the Project Cost.

Answer: Fast-track the project by compressing the schedule without increasing and expanding the costs.

Learn more: Project Cost: Why is it important for Project Managers?

2. You are the Project Manager for XYZ Project. You found that the Project is delayed, and it cannot be completed on time. It may create a loss of $5000 per day for the Organization if any preventive action is not taken. So, you have planned to get the approval from the management to change the relationship between several of the work packages, so that they start in parallel instead of sequentially. This is an example of?

Answer: Fast Tracking.

3. There are two activities with Finish to Start sequences. The duration of the first activity is 12 days, and the duration of the second activity is 10 days. The estimated time completed for these activities is 22 days. The Customer asks you to complete these activities within 19 days; you review his request and agree to do so at no extra cost. Now, you plan to start the second activity three days before the first activity completes so that both activities can be completed in 19 days. This process is known as:

Answer: Fast Tracking. In fast-tracking, those activities planned in sequence, performed in parallel or partially parallel to reduce the schedule.

4. You are the Project Manager for a Construction Project. You found that the project is delayed and decided to compress the schedule so that you can complete the project on time. You asked your team to perform both electrical and plumbing activities in parallel, instead of the plumbing activity starting after completing the electrical activity. The action which you have taken is an example of?

Answer: Fast Tracking

5. The Schedule Performance Index (SPI) for your project is 0.86, which is behind the Schedule. Management asked you to fast track your project. You informed the management, that the consequences of Fast Tracking are:

Answer: 1) Rework.

               2) Increases the Risk.

6. You determined that there are a number of activities in the Project Schedule Network Diagram, that can be performed in parallel by overlapping Finish-to-Start Relationships or making Start-to-Start relationships. Which Schedule Compression technique are you using?

Answer: Fast Tracking

7. As the Project is delayed and the Schedule Variance for the Project is .83, you decided to utilize high-end resources from some non-critical path activities to some critical path activities; and also decided to perform some project activities in parallel to bring the project back to normal. This is an example of?

Answer: Fast Tracking

Related reading: 10 Essential Time Management Strategies

Benefits to the project

The two important Schedule Compression Techniques (Fast-Tracking and Crashing) are used by the Project Manager during the lifecycle of the Project from Project Initiation to the Project Closure to bring back the project in line with the Schedule Baseline without changing the project Scope.


This article explains in detail the specific applications of Fast-Tracking and Crashing, these are the two Schedule Compression Techniques for your project, if you want to bring back the project in line with the Schedule Baseline without changing the Project Scope. Fast Tracking always performs activities in parallel without any addition of Resources but Crashing performs activities in sequence by including additional resources to reduce the Project Schedule.

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M. Suresh Kumar