Is poker a game of skill or chance? It’s not a one-or-the-other proposition. Even the best poker players in the world will tell you that there is an element of luck, but their skill is what keeps them at the top — in the long run, better players will win more often than worse players.

Now there’s more research to prove it:

Drawing on a database of 456 million player-hand observations from a year’s worth of online games, we first investigated how consistent player performance was. This revealed substantial evidence of the role of skill in successful play.

For instance, players who ranked in the best-performing 10% in the first six months of the year were more than twice as likely as others to do similarly well in the next six months. And, players who finished in the best-performing 1% in the first half of the year were 12 times more likely than others to repeat the feat in the second half. Meanwhile, players who fared badly from the start continued to lose and hardly ever metamorphosed into top performers.

The point here is that performance is predictable. In a game of chance there would be no correlation in the winnings of players across successive periods, whereas there would be in a game of skill. So we know for sure that poker can’t be a game of pure chance.

Read more about the researchers’ conclusions here.