Geez, another really good post over at Coding Horror on best case vs. worst case time estimates. Jeff is reading McConnell’s book on Software Estimation.
If you ask a developer to estimate a set of features, the developer will often come back with an estimate that looks like this:
Feature Estimated Days Alpha 1.5 Bravo 1.5 Charlie 2.0 Delta 0.5 Echo 0.5 Foxtrot 0.25 Golf 2.0 Hotel 1.0 India 0.75 Juliet 1.25 Total 11.25 If you then ask the same developer to reestimate each feature’s best case and worst case, the developer will often return with estimates similar to these:
Feature Best Case (days) Worst Case (days) Alpha 1.25 2.0 Bravo 1.5 2.5 Charlie 2.0 3.0 Delta 0.75 2.0 Echo 0.5 1.25 Foxtrot 0.25 0.5 Golf 1.5 2.5 Hotel 1.0 1.5 India 0.5 1.0 Juliet 1.25 2.0 Total 10.5 18.25
I really gotta get me that book!
