How much of a game is luck and how much is skill?
It varies enormously, and the useful way to think about it is not as a single ratio but as how many decisions and how many trials a game contains — because luck averages out and skill accumulates.
The two extremes. Chess and Go have no randomness at all: identical starting positions, perfect information, and every outcome determined by decisions. Snakes and ladders has no decisions whatsoever — the outcome is fully determined once the dice are rolled, and the players are spectators.
Most games sit between, and the interesting question is how they mix the two.
Why randomness is not a flaw. It serves genuine design purposes:
It makes the outcome uncertain, so a weaker player can win occasionally — which is what keeps people playing. A game where the better player always wins loses its audience quickly.
It forces adaptation rather than memorised plans, which is why games with randomness often require more flexible thinking, not less.
It creates drama and moments worth recounting.
It conceals information, enabling bluffing and probabilistic reasoning.
The crucial distinction: input randomness versus output randomness.
Input randomness occurs before your decision — the cards you are dealt, the tiles you draw. You then make decisions given what you received, so skill lies in playing your position well. This is generally considered good design.
Output randomness occurs after your decision — you commit to an action and a die determines whether it works. This can feel arbitrary, because a good decision is punished. Many designers prefer to limit it or to give players ways to mitigate it.
Why poker is a skill game despite the cards. Any single hand is dominated by luck. Across thousands of hands, the variance averages out and skill differences dominate — which is why sample size is the whole argument, and why poker's legal status has hinged on it in several jurisdictions.
The practical measure. A game is more skill-dependent the more meaningful decisions per game it contains, and the more games are played. A single game of anything tells you little.