Projects come in all kinds of lengths and sizes. In light of this how long should your activity durations extend?
Activity durations should be sized to suit the respective project length. Activity durations that are too short result in schedules that are too detailed and cumbersome. On the other hand activity durations that are too long make it difficult to perceive the true project situation.
The Defense Contract Management Agency (DCMA) 14-point assessment limits the number of tasks longer than 44-days, which approximately equates to 2-months. There are other helpful rules to guide specification of task length in your schedule.
This article provides a quick tip to help the scheduler determine the appropriate task length for a given schedule.
It is important to consider the reporting cycle when determining the appropriate length of schedule tasks. The reporting cycle for most schedules is one month. Some guidelines say to make tasks not longer than a reporting period. The principle is that tasks reported as in-progress in more than one reporting period likely have issues.
The DCMA 14-Points, again, says limit the number of tasks longer than 2-months (or 2 reporting periods). A task longer than two reporting periods is most likely a task in trouble. The appropriate task duration helps drive this troubled task warning mechanism. So for more insightful schedule reporting limit task durations to, perhaps, one, or, most definitely, two reporting cycles.
Because project durations vary significantly another guideline helps determine task durations. This guideline is known as the 1% to 10% rule. This guideline provides a minimum and maximum task duration. To bracket lower and upper task duration limits use 1% of the project duration as the minimum and 10% of the project duration as the maximum.
Using the 1% to 10% rule, a four month long or 80 business day project computes a minimum duration of 0.8 days and maximum duration of 8-days. Exceptions to the 1% to 10% rule include level or effort activities, such as project management or administrative tasks, which span the project duration, and milestones that are zero duration.
When it comes to projects you want to avoid scheduling too little detail or too much detail. Limit task durations to one reporting cycle to trigger a troubled task alert warning when in-progress tasks extend through two reporting periods. The 1% to 10% rule may also help bracket the minimum and maximum suitable task durations for a respective project. You can read more on the DCMA 14-Point Assessment and High Duration Tasks here.
For more guidance on scheduling consider “Forecast Scheduling with Microsoft Project 2010” by Eric Uyttewaal.