Nifty. For a while I was working on a commercial drag-and-drop tool for PERT-style estimation[0].<p>It foundered on the rocks of Angular. But I did enjoy doing research on PERT and estimation generally.<p>My suspicion is that PERT works more through the "unpacking effect" than through the statistical stuff. PERT sorta-kinda resembles a simplistic normal distribution, which is nonsensical in a lot of ways.<p>Later operations research got way, way more sophisticated. But it is my suspicion that stuff like stochastic project networks have produced more PhDs than accessible estimates.<p>The unpacking effect is more compelling, because it's a way to offset the planning fallacy that humans are prone to. Make people break down a task <i>before</i> they estimate, and they will give a higher estimate. This is because humans systematically forget to include lots of tasks.<p>In software engineering, for example, off-the-cuff estimates typically don't include stuff like time for documentation, waiting for CI and so on. We subconsciously over-weight the tasks that we understand best: the coding.<p>[0] <a href="http://confidest.com/" rel="nofollow">http://confidest.com/</a>