OK, this one is controversial. Software estimating. How to do it good, or good enough? First of all, when talking about the subject we all can learn a lot from Glen Alleman who bring quite an uncommon perspective to the area as he’s based in industries which tolerate missed deadlines with much less patience than the average.
Now, what’s the point? If you asked me how software estimating should be done I’d direct you to Steve McConnell book on the subject. Believe me or not, he didn’t write anything good (if anything at all) about role of wild guessing in software estimation. Which doesn’t make me avoiding wild guesses at all times.
Actually sometimes I make good use of them.
Now, go flame me.
What’s the use of wild guesses instead of proper estimation? Wild guesses don’t have to be so wild if you ask a right person. If I ask my development manager how long something would take and it’s a piece of software he’s fairly familiar with in vast majority of cases he’ll come with some guess. It should be reasonable enough to judge whether it’d take 9 months to do the job or rather just a few weeks.
I don’t consider that as a full-blown estimate. It’s hard to use it as a base to create a schedule but still it’s a valuable feedback to judge whether and when your team is capable to overtake the project or decide if the whole thing is worth further presales effort. If you need to develop a bunch of tools which your competitors already have in their product portfolio chances are good you won’t match their schedules and/or prices. If you add that your team is backed up for the next half of the year it’s probably not worth investing effort to do more than just getting first coarse-grained approximation.
Yes, every wild guess should be considered very carefully since after all it’s, well, just a wild guess not an estimate done according to rules. However doing proper estimation is quite an effort and sometimes you need something rough but quick instead of exact but demanding.
And remember: don’t ever, ever allow your wild guesses to be sent to sales department.