I definitely enjoyed the meet up.
In defence of my fairly poor estimate I was unconvinced by the assumption that all the maise in mexico was eaten by mexicans. It seemed that this was an uncontrolled assumption but i felt that i could put reasonable bounds on all the assumptions in the land area estimate (if you're asking, yes, the final answer did fall within my 90-10 bounds :) ).
Hopefully with a bit more notice we can get a few extra people next time but i think it was a great idea to get the ball rolling. Thanks to Tomasz for organising.
In defence of my fairly poor estimate I was unconvinced by the assumption that all the maise in mexico was eaten by mexicans.
Why does it seem so bad? Food products are the most common products countries defend with tariffs and similar policies, and if Mexico is not self-sufficient then even more reason for all consumption to be local.
Here's a brief summarly of the first meetup. It took place on cafe on top of Waterstone bookstore on Saturday 2009-04-04, starting at 14:00 and lasting until about 17:15. Six people showed up: Tomasz (me), Michael, Will, Julian, Shane, and Marc.
We started with a game of estimation warewolf - there was 1 decider, and 3 participants, one of the dishonest. 2 people showed up later, so they joined the game as openly honest. I don't think the decider position was really necessary, we could simply randomly assign people to honest and dishonest set. Or if the dishonest guy was necessary, we were confused enough without any active help. The subject was "maize production of Mexico". We did our estimate twice. First based on what Mexicans are likely to eat. Our estimates were:
Most of the time we discussed it first, and then took the median of our guesses as the estimate. The discussion was really the fun bit, I'll give a few examples later. There was a lot of joking about anchoring effect, but I don't think there was that much of it.
Then we hid the first estimate, and tried the same question again, in a different way, estimating:
That was almost two orders of magnitude off. I was so sure that the second estimate failed any sanity check that I took a 10000:1 bet against it (conditional on our arithmetics being correct), taking 1p against 100 pound donation to the Singularity Institute. At this point we gave our point estimates, and checked it against reality. If my notes are correct, they were:
So the Singularity Institute isn't getting their money, our first estimate was very accurate considering our lack of clue about the subject matter, the second was widely off, and everybody except Marc gave more credence to the first. They might have been convinced by me taking that absurd bet via Aumann's Theorem.
Errors on individual estimates were:
After that, we just had chat about the Cabal on Wikipedia (which doesn't exist), tvtropes, early Internet sentimentalism, option pricing, financial crisis, quantum computers, prospects of AGI, and other random subjects. We also invented a new way of paying the bill "by the bailout" - everybody puts as much money on the plate, or takes as much from it as they want, as long as the final result sum was right.
We're most likely going to do the next meeting in about a month, in the same place. Here's the picture. Please correct me if I misremembered anything important.