Saturday, April 14, 2007

The dark art of cheating software estimates - Part two.

Just a quick addendum to my previous post about software estimates (and how to fool yourself cheating with them).

The most effective trick to miss a deadline (and the following one) is to put unrealistic estimations over developers activities. To achieve this result you have basically two ways.

Define the estimates at the wrong level
This normally happens when the team leader defines the activities and assigns them over the head of the developers. Experienced developers know better what should be done and which activities take time, so you should rely on their point of view, after all they're the experts in their domain. Imposing an estimation on the developer's head has also the undesired effect to cause an emotional drift in case of activities taking longer than expected. A young developer could assume that he is the problem (and maybe the real problem is just something forgotten at a higher level) and feel responsible for the delay. If you just say "You have 3 days to finish this" you might end up having the only crappy piece of software the developer was able to write in those three days.
And, of course, skills and environmental factors are different, so the same activity could take 2 days if assigned to one developer and 4 to another one. If the estimates are coming from above, it's easier to forget about that, when quickly reassigning activities.

Ok, this is just something that might happen. I am not saying that one should completely rely only on developers' numbers. A good team leader has its own estimates in place, that can be used manage risk related to optimistic developers, and so on. But this is an activity that should be performed behind the scenes (my first team leader always added 30% to my developer estimations). Comparing developers estimates with yours could also help to spot potential problems, like activities that shouldn't take that much.
By comparing different developers estimations on similar tasks, you could also spot if somebody found a smarter way to do something, and have him teach to the others (or discover that somebody is not finishing the activity and leaving some dirt under the carpet as an undesired gift for the following iteration). Put in another way you should rely on the developers on the estimations and take yourself the burden of find out how to speed up activities.

Asking estimations in the wrong way
One thing you should never do is ask "Will it be finished for Tuesday?" and - even worse - the follow-up "You told me this was going to be finished for Tuesday". Of course, in the middle, everything can happen. If you want to be hated you can ask the question one day, then interrupt with a higher priority task, then on Tuesday ask the follow-up, with a blaming pitch.
The point is that, as a leader, you shouldn't forget the effect of your role. A milestone should be a leader's problem, not a developer's problem (and shouldn't be managed in terms of blame anyway). Asking a question in this way is no different from a woman coming out from the hairdresser with a new "transgressive" haircut asking "How do I look?". It's just a compelling invitation to lie.
At the end, the numbers are exactly the ones the team leader wanted, but in this case the blame is all on the developer. Playing this trick, is unfair, doing it repeatedly is just a way to increase pressure and to threaten team alchemy.

The right way to put question is "How much time you need to do this?" and then do everything possible to ensure that all of this time will be spent on that activity. A good leader manages pressure from above and should shield team from it. If the collected numbers are too high, there is probably a problem, which needs to be investigated and possibly solved, soon.

Don't forget that providing a detailed estimation of the activity, is an activity itself. It shouldn't take a day, but be careful when you get an immediate reply; it's a sign that somebody isn't probably thinking enough. So leave your developers the time to think about what should be do and how much time will be needed. As Joel Spolsky states, this is design activity, after all.

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