Compression (Essentials)

Schedule Compression refers to the amount of effort required to complete the remaining work on a project compared to the same amount of final work remaining in the baseline schedule. It quantifies how much the schedule has been accelerated and/or how much float has been eroded, and indicates the likelihood of meeting the planned end date. 

SmartPM Categorizes compression risk using this color coding:

• Green (0-14%): Compression is within an acceptable range
• Yellow (15-24%): The project is still feasible but may require extra time, increased pacing, or labor to complete on time
• Red (25% +): The project end date is at risk due to the extra time and work required. 

Example:

Most schedules are built on a five day calendar working Monday through Friday. Each day of the week is about 20% of the work week. When the schedule is compressed by 20%, it will be necessary to start working Saturdays to finish on time. Once your schedule becomes compressed by 40%, it will be necessary to work Saturdays and Sundays to finish the project on time.  In a scenario where you don't have access to overtime, or additional manpower, your project will be delayed. 

Causes of Compression:

Compression can result from various factors, including:

• Acceleration Due to Changes to Remaining Work: Decreasing the remaining duration of an activity or stacking trades means you need to complete more work in a shorter period of time. 
• Slower- than-Planned Progress on Non-Critical Activities: If progress is not occurring as planned and float erodes, a non-critical activity can become critical, leading to schedule compression.