4 ms·
This is such.an elegant way of explaining the problem: For every step in a project, there’s about a 50% chance of completion under or on the median step comple
by zacharycohn 11y ago
This is such.an elegant way of explaining the problem:
For every step in a project, there’s about a 50% chance of completion under or on the median step completion time. And there’s about a 50% chance of not. If a project is composed of 2 steps, the probability that both steps are at or under their median times is 50% * 50%, or 25%. For a 3 step project, it’s 50% * 50% * 50%, or 12.5% and so on. If a project has 6 steps, the chances of some of those steps going over its median is greater than 98%.
- jldugger 11y agoBut some of those steps will go under the median as well. The problem is the distribution is not normal -- if the range of possible outcomes below the median n is [0,n], the range of possible outcomes above the median is far wider than [n,2n]. Going by the chart the article offered, I suspect a sort of mixture distribution: the better understood tasks have normal distributions, and the poorly understood ones have bullshit estimate distributions.