Project Management: Some Thoughts on Planning I

One of the issues in Project Management (PM) planning is that the planner idealizes a resource and activities performed by it much like a machine. Unlike machines whose uptime can approach 100%, a human resource can work at most 90% of the available time (aka utilization time), the remaining 10% being typically associated with interruptions – internal emails and meetings, casual communications, pauses, etc. For resources split between projects or operations the utilization time can be at most 70%, however a realistic value is in general between 40% and 60% on average. What does it mean this for a project?

So, if a resource has a volume of work W, the amount of time needed to complete the work would be at best W/UT, where UT is the utilization time of the respective resource. “At best” because in each project there are additional idle time resulted from waste related activities – waiting for sign off, for information, for other resource to complete the time, etc.

The utilization time is not the only factor to consider. Upon case, the delivered work can reach maybe on average 80% of the expected quality. This applies to documentation and concepts as well for written code, bug testing and other project activities. To reach in the range of 100% one more likely will need 4 times of the effort associated with reaching 80% of the expected quality, however this value is dependent also on people’s professionalism and the degree with which the requirements were understood and possibly achievable. Therefore, the values vehiculated can be regarded as “boundary” values.

Let’s consider a quality factor (QF) which has a value of 1 for 80%, with an increase of 0,25 for each 5% of quality increase. Thus, with an initial effort estimation of 100 days, this is how the resulted effort modifies for various UT and QF values:

Considering that a project can target between 60% and 95% UT, and between 80% and 95% quality, for an initial estimation of 100 days the actual project duration can range between 117 and 292 days, where the lowest, respectively the right bound values are more realistic.

The model is simplistic as it doesn’t reflect the nonlinear aspect of the factors involved and the dependencies existing between them. It also doesn’t reflect the maturity of an organization to handle the projects and the tasks involved. However, it can be used to increase the awareness in how the utilization time and expected quality can affect a project’s timeline, and to check on whether one’s planning is realistic.

For example, at project’s start one can target an UT of 70% and a quality of 85%, which for 100 days of estimated effort will result in about 178 days of actual effort. Now diving the value by the number of resources involved, e.g. 4, it results that the project could be finished in about 44,5 days. This value can be compared then with the actual plan in which the activities are listed.

During the project it would be useful to look on how the UT changed and by how much, to understand the impact the change has on the project. For example, a decrease of 5% in utilization time can delay the project with 2,5 days which is not much, though for a project of 1000 days with talk already about one month. Same, it will be helpful to check how much the quality deviated from the expectation, because a decrease in quality by 5% can result in an additional effort of extra 8 days, which for 1000 days would mean almost 4 months of delay.