Estimates of effort and duration for a new software project often have to be adjusted to deal with an imposed target delivery date or a constraint on staffing. Estimating methods assume an effort/duration trade-off relationship based mostly on theory or expert judgment. This paper describes a process for analyzing actual project effort and duration data which is designed to explore the trade-off relationship. I assume a reference relationship of a simple power-curve with variable power "N" and use this (a) as a means of comparing the trade-off relationships assumed by four well-known estimating methods, and (b) as the basis for a process to analyze actual project data. Results are presented of applying the process to 16 sub-sets of project data. These suggest, for example, that the value of "N" differs between new development projects and enhancement projects. The Web Extra presents more results for each step in the effort-duration trade-off process described in the main article. © 2012 IEEE.
