Ziggeh wrote...
How does one select a random sample when the intitial population are people invested enough to have made themselves known as "fans"? You need to know what that's based on to use the data, but even if it's something fairly wide like previous purchasers, that doesn't account for people who weren't fans previously. It would be exclusive, and therefor wouldn't represent the whole of your population. If it was even wider and by "fans" it means "some people" then it's including people who are irreleveant.
After that it's your standard things like: selection. If the poll was say, conducted by e-mail you'd have yourself a self selection poll again, only the extremes would respond. sample size, leading questions etc
You're stretching here. My turn to drag you from the brink

First of all, we don't actually know the definition of "fan". Metholodogy, as you pointed out, is unknown.
Secondly, and more importantly, any poll regarding a very specific product like ME3 must in fact be limited to either the people who are playing, or will potentially play the game. Complaining about how a poll only covered Mass Effect 3 players and not the whole population - including toddlers and old people who don't play video games - is on the silly side.
You can, in fact, limit yourself to only a segment of the population when doing a survey, and that segment can be "current ME3 players". You just need to specify this segment as part of the study.