Explains how labor, travel and other costs can be distributed over the duration of the resource or task
Labor Efforts vs. Time
When you plan for a resource to do a task you typically enter the total effort over the duration of that task, for example 1000 hours over a six month task. This could be one person full-time working the same number of hours each day (linear distribution) or several people up-front doing the bulk of the work in the first two months with one person part-time for the last four month (up-front distribution). It could be a gradual ramping up of resources over the task, peaking approximately half way through the task and then tailing off (bell-curve distribution). These different distribution options are shown graphically below.
Figure 1 - Bell Curve Distribution
Figure 2 - Linear Distribution
Figure 3 - Front Curved Distribution
Figure 4 - Back Curved Distribution
Figure 5 - Stepped Distribution
Which Distribution Curve Should I Use?
If you do not select a distribution curve then a linear or even distribution is assumed. This makes sense in the majority of cases, especially when you are not sure how the labor should be distributed over the duration of that task or WBS element. It is also the simplest and easiest to check the costs and hours in the costing model - since the hours and resource each calendar month will be directly proportional to the number of working days in that month overlapping the task or WBS-resource assignment start and end dates. "Full-time equivalent" (FTE) calculation of effort as task duration x FTE is also based on a linear distribution assumption.
- You can calculate effort from "full-time equivalents" and distribute that effort over the task using a non-linear distribution curve
For larger tasks having multiple resources assigned and having significant costs, it may be better to select a distribution profile best suited to the nature of the task you are planning. For example many projects with multiple resources will ramp up at the start - as people are recruited or on-boarded and the exact plan is being ironed out - and then ramp down at the end, as resources are rolled off. A stepped distribution curve suits this profile nicely, or a bell curve if the ramp up and ramp down is so gradual the resource load is only briefly peaks at the mid-point in time.
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