In project management, planning and scheduling are core activities. But what I notice is that the work package size and duration is here rarely an important topic. My experience shows that it should be a topic, because work packages are usually planned so large that they can spin out of control. This is also one reason why projects often extend dramatically beyond their schedule. In this article I give you you some hints and rules on how to plan your work package size reasonably so that you do not lose control afterwards during the project execution. Read on and learn more.
What Determines the Work Package Size?
From the work breakdown structure planning you know, that the structure of a project should be defined in such detail until work packages are created that can be planned and controlled. These are then handed over to an organizational unit (working group, specialist department or external contractor) or a project team member for execution.
A too fine detailing of the project object reduces the transparency and worsens the cost-benefit ratio of the project planning. Too little detailing makes project monitoring more difficult and increases the risk of exceeding deadlines and costs. The work package size should therefore be chosen in such a way that the work package can be monitored reliably. If you want to make sure that the work packages have a suitable size and duration, you can apply the following rules of thumb by Eric Verzuh.
Rules to Define the Work Package Size
Die 8/80 Rule
No work package should be smaller than 8 or larger than 80 person hours in duration. This will result in your work package being between 1-10 days long.
The Reporting Period Rule
No work package should be longer than the interval between two status dates. That means, if you have a weekly status meeting, then the work packages should not last longer than one week. This rule is useful when it is time to report progress. Then you will no longer talk about work packages that are 25%, 40% or 68% complete. If you follow the weekly rule, then a work package is either finished (100%), started (50%), or not started (0%). No work package should have a status of 50% for two consecutive status meetings.
The “if it’s useful” Rule
If you consider whether to break down the work packages further, there can be three reasons for this:
- The work package is easier to estimate. Smaller work packages bring less uncertainty and allow more accurate estimates.
- The work package is easier to assign. Large work packages assigned to many people tend to lose responsibility. Breaking down work packages into smaller parts makes the responsibility clearer. Smaller work packages also give you greater flexibility in scheduling and resource planning.
- The work package is easier to monitor. The same logic applies here as for the reporting rule. Smaller work packages give more tangible status points, so you have more accurate progress reports.
If breaking down a work package in a certain way is not useful—that is, if it doesn’t make it easier to estimate, assign, or track—then don’t break it down!
When Very Small Work Packages Make Sense
Can you imagine breaking down work packages into 1-hour increments? You might answer me that this is micromanagement. For projects with a duration of several months this is probably not useful. But for very short projects this is common. For example, preventive maintenance for a manufacturing plant may require to shut down the plant for 2 days or a week. Such projects are usually planned in hourly increments. This allows you close coordination of all parties involved and allows to quickly identify work that is delayed.
In our neighborhood, a winding railroad line of about 20 kilometers (12 miles) with several bridges and tunnels was recently renovated. 37 million Dollars were installed in 33 days. What do you think, was the work packages duration here also a few days long?
I hope you found this article informative and you could learn something.
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Book recommendation: Eric Verzuh: The Fast Forward MBA in Project Management
