In the past few weeks I have seen a ton of questions floating around about users of project management systems wanting to see reporting showing resource capacity vs. demand. Now you might be saying “But Brian, that is pretty common. Doesn’t EVERYONE want this kind of data from their PM system?” to which I would reply “Certainly, but these requests were different in that they all wanted to see it for time periods going out as far as 2 years into the future.” My question is what is someone going to do with a comparison between demand (scheduled work) and availability that far into the future? The instant answer I always get is that they want to see how the current load of projects scheduled is placing demand on their resources and that is a good answer. But in my opinion most organizations are just not good enough at scheduling and estimating and forecasting to make schedule data that far into the future of a quality that would support any real decision making around demand\capacity problems. Schedules are hard enough to get accurate for the next 2 months let alone the next 2 years.
There are industries or environments\situations where the type of projects being done are easy to estimate because they have a high similarity with projects that have already been done but for the most part capacity\demand data derived from project schedules should be looked at as ‘fuzzy’ if the time period of the data is farther out than a few months and even fuzzier if it is more than a year out.
There are decisions that can be made based on this data but they should be made with the knowledge that those numbers could swing wildly in some cases depending on changes to the project as it moves forward. The adage that some data is better than no data holds true for the most part but ‘some data’ that is highly suspect but still used in the decision making process as if it was certain is worse than no data.
When you are looking at data that depends on the quality of your schedule estimates and project WBS you need to think about that quality when you make decisions based on that data. Where are those estimates coming from? Are they top-down estimates (like many that are that far out into the future) or are they bottoms-up estimates coming from the resources that will do the work (hard to do when the tasks in question are months or even over a year in the future?