“The further a project progressed, the more accurate the estimates for the remaining effort and time became”
(Barry Boehm, “Software Engineering Economics“, 1981)
NASA also came to the same conclusion that in the beginning of the project life cycle (i.e. before gathering of requirements) estimations have in general an uncertainty of factor 4. This means that the actual duration can be 4 times or 1/4th of the first estimations…
I felt very free to add my own interpretation of the different point-of-views with cool pastel colors as a sneak-peak cool-beta-preview of my next post.