I am really good at estimating. By which I mean, I can estimate anything, even if my estimates are not accurate. If you ask me for an estimate – on anything – I can give you one. I never let absence of facts stand in my way.
However, many people are horrible at estimating. You ask them for an estimate – on anything – and they can’t do it. They don’t know where to start. Even if they should be able to estimate something, based on their experience and knowledge and the availability of facts, they just can’t do it. It isn’t that they don’t want to commit – they might say that’s why, though – it is because they honestly can’t make an estimate.
In the past I have found this frustrating. I think to myself, “if I had your experience and these facts, I could form an estimate immediately”. Experience has taught me that getting mad and putting pressure on someone to give you an estimate when they think they can’t doesn’t help. (This is especially true if the “someone” in question is your wife or daughter :)
But recently I’ve found a great trick. You can help people form estimates by using binary searching. People are much better at comparisons than they are at estimating. This is true even though all you need to do to form an estimate is iterative comparisons.
The technique of binary searching is well known in computing, it is part of every freshman computer class. It is a routine technique; suggesting that a programmer use binary searching is like suggesting to a fish that they swim. However non-nerds might not be familiar with the technique so here’s a quick example.
See how it works? Each question is a comparison, and each result divides the number of possible answers in half.
Okay, so let’s say you want someone to give you an estimate. Instead of asking them directly for the estimate, ask them to do a series of comparisons, each of which cuts the possible answers in half. Pretty soon you have a reasonable estimate. Here’s a real example:
Be careful always to phrase each question as a comparison. Don’t ask “will this be about X?”, instead ask, “will this be more than X?” I don’t know why, but humans do better with “more than” -type questions.
This technique even works within yourself. Let’s say you have a project to do. (You need to decombobulate a qwork.) You can’t form a decent estimate. Ask yourself – will it take more than a month? More than two weeks? More than a week? More than two days? More than eight hours? Etc. You know more than you know!
I hope you find this as useful as I have!