3 ms·
There's a simple method for software estimates that has worded well for me in practice. Imagine how long it should take if all goes smoothly, then multiply by p
by nicky0 6y ago
There's a simple method for software estimates that has worded well for me in practice. Imagine how long it should take if all goes smoothly, then multiply by pi.
- kqr 6y agoWhat does "worked well" mean? What percentile do you practically end up at when you go back and verify after completion?
- nicky0 6y agoBy "worked well" I mean that x3 is the "about right" factor. As software engineers we tend to be optimisitic and so when I think "it'll take about a week", that's assuming no unforseen complications. I'm afraid I haven't conducted a detailed a statisical analysis, however. The pi method is in truth just a joke between myself and a former project manager. There's nothing magic about pi exactly. I imagine each person ought really to come up with their own mental multiplier based on their own tendency to underestimate. But 3 isn't a bad starting point for iteration.
- kqr 6y agoI guess I'm asking what "about right" means. Does it mean you finish faster than that number 50 % of the time? 90 % of the time? No statistics necessary, just your gut feel.
- nicky0 6y agoAh, good question. First instinct says 'success' should be statistically 50% each way. Right in the middle of the bell curve. But on second thought, being behind estimate half the time would be pretty sucky. So I'd like to bring the peak of the curve onto the early side of the line. I guess ultimately it depends on the question being asked of the estimator & the implied confidence interval. What do you think?