|Authors||K. J. Moløkken-Østvold, N. C. Haugen and H. C. Benestad|
|Title||Using Planning Poker for Combining Expert Estimates in Software Projects|
|Afilliation||, Software Engineering|
|Publication Type||Journal Article|
|Year of Publication||2008|
|Journal||Journal of Systems and Software|
Combination of expert opinion is frequently used to produce estimates in software projects. However, whether, when, and how to combine expert estimates is poorly understood. In order to study the effects of a combination technique called planning poker, the technique was introduced in a software project for half of the tasks. The tasks estimated with planning poker provided: 1) group consensus estimates that were less optimistic than the statistical combination (mean) of individual estimates for the same tasks, and 2) group consensus estimates that were more accurate than the statistical combination of individual estimates for the same tasks. The set of control tasks in the same project, estimated by individual experts, achieved similar estimation accuracy as the planning poker tasks. Moreover, for both planning poker and the control group, measures of the median estimation bias indicated that both groups had unbiased estimates, because the typical estimated task was perfectly on target. A code analysis revealed that for tasks estimated with planning poker, more effort was expended due to the complexity of the changes to be made, possibly triggered by the group discussions.