Estimating market size

I will just toss out, that many Cons/Toy Fairs/etc have demographics that might help you in this area. Though from what I have seen, the demographics are not as detailed as how many people will play "my game" or even "game X". Not sure you can get that specific unless you did some population sampling (say by attending X cons and surveying people about your game, maybe get them to playtest a prototype and ask them, would you buy this game, yes/no).

If you want a high level idea, take a look at the exhibitor information for GenCON (www.gencon.com), it will contain some basic demographics information about different types of games and the number of people playing each. (or at least last years exhibitor packet contained this type of information).

You could potentially base some production values on these types of numbers. If you figure that 30,000 ppl attend GenCON, and their demographic states that 30% of those play board games (9000), what percentage of those would buy "my game"? Factor in that other new games by known designers will most likely crush your dreams of selling 9k, figure at least 4500 ppl wont even notice your game. The other 4500 might notice, but of those lets say only 2250 ppl have any money left by the time they get to you, factor in that no one has heard of your game, 1125, take into account that after playtesting at your booth with the available demo you have set up, only 550 even like the game, but even then half of these will not be sure if friends will play it, so maybe 275 ppl might buy the game, but the price might scare another 135 ppl away. So at this point from 30k you are down to about 140 ppl that may actually buy your game.

From here figure that you might attend Y different shows in hopes to sell your game. Maybe get some distribution contacts from which you might be able to add Z more copies.

And finally you have some idea of the number of games you might want to produce. At this point assess if it is cost effective enough to only produce half the the number of copies you "expect" to sell. So for my long winded example, 140 per show times 6 shows, 1 distributor say who will gamble on 100 copies, so I might consider something like 1000 copies to start, but wait since this is a new game, maybe consider only half of the 1000 for 500 copies and what would be my largest total for the year. Unless once I went to a few shows, I sold out (which is a blessing), then I would produce more. At this point you really need to consider if producing 500 is cost effective, since higher productions qty will reduce your final price, this will impact both gamers and distributor interest in your game.

As with all games, you just never really know how many you will sell, unless your someone like Knizia, which means you can sell 10k just by having designed the game. :)

As a side note, this is the current idea behind my production scheme for Infamous Games. So far I have still estimated a little high, based on actual copies sold. Though I am refining each year (and I do not get a chance to attend 6 shows a year, so that might be an issue).

Ah well, good luck!