That's quite simple, really. If you've carefully tracked your past projects, by comparing tasks from the planned project to those you've done of similar complex

That's quite simple, really. If you've carefully tracked your past projects, by comparing tasks from the planned project to those you've done of similar complexity you can make more realistic estimations. It works best on a long-running project. When you plan a new feature, you can gauge really accurately at what speed your current team developed a feature of comparable complexity, so as you go forward you get better and better estimates. Joel Spolsky explained it there: http://www.joelonsoftware.com/items/2007/10/26.html http://www.joelonsoftware.com/items/2007/10/26.html