Overview

It is common sense to take a method and try it.

If it fails, admit frankly and try another. But above all, try something.

Franklin Roosevelt ^[1]

Regression Analysis

Regression analysis is a term applied by mathematicians to the investigation and analysis of the behaviors of one or more data variables in the presence of another data variable. For example, one data variable in a project could be cost and another data variable could be time or schedule. Project managers naturally ask the question: How does cost behave in the presence of a longer or shorter schedule? Questions such as these are amenable to regression analysis. The primary outcome of regression analysis is a formula for a curve that "best" fits the data observations. Not only does the curve visually reinforce the relationship between the data points, but the curve also provides a means to forecast the next data point before it occurs or is observed, thereby providing lead time to the project manager during which risk management can be brought to bear on the forecasted outcome.

Beyond just the dependency of cost on schedule, cost might depend on the training hours per project staff member, the square feet of facilities allocated to each staff member, the individual productivity of staff, and a host of other possibilities. Of course, there also are many multivariate situations in projects that might call for the...