Alright, so estimates suck and we all know it. Plenty of reasons why and models to try to get it right. But hey, were human and we're subject to all kinds of flaws. Well, here's a method that a colleague and I came up with as a joke at first. But now that I think more about it...it seems to be just as good (maybe better than) as any other method.
What you'll need:
1 sheet of paper, whatever size.
1 writing device (pen, pencil, marker, crayon, go crazy
1 coin with 2 different sides (heads/tails)
What to do:
Step 1: Prepare by drawing a circle on the paper and place paper on flat horizontal surface (desk or floor).
Step 2: Pick a number for the task as a starting point. esty := n;
Step 3: Flip the coin at the paper.
Step 4: If coin lands in circle, return esty.
Step 5: If coin is heads, increase esty and loop back to Step 3.
Step 6: Decrease esty and loop back to Step 3.
Why is this method awesome? Because first of all you use your gut to produce the original estimate - always go with your gut.
Second of all, if you really feel strongly about your number, then you'll hit the circle. Else, the randomness of the coin introduces some real-world randomness that you'll encounter in the real-world...for real!
Some models call this a Monte-Carlo factor and use some pseudo-random number generator to add pseudo-reality to the equation...that's weak compared to the good old trusty randomness of a Wheat-Back Penny!
Be sire to break down those tasks a bit. You wouldn't want a single coin toss to determine the fate of the whole project - you want more samples to produce the desired results!
Oh, and generally I'd use a scale for the numbers like: .5, 1, 2, 4, 8, 16, 32,... In hours. If you throw bigger than 32 (that's more than full week if you really get down to it) maybe you better break it down a bit more.
Ok, there you have it! Make those circles and start tossing your way to successful estimation!