[ChicagoRy]

They talk about this in mathematics of poker.

They use calcs obviously to figure it out, but if an opponent raises the first hand of the match it is more likely he's raising a ton than if he folds the first hand of the match (he is more likely to be a tighter player). The larger sample you have the less margin of error you can factor into your decision making.

I think most people ignore the first 5 hands of a match unless villain has raised like 5-10x each time. I think this is a semi leak in a lot of players. I may be wrong, but it should probably factor more into people's decisionmaking if villain raised 3 of the first 5 buttons or whatever, than if he did 1 of the first 5. Nothing to dramatically change things, but it's the difference in a lot of situations that are semi close in your mind that come up early.