Return to player is the percentage of total stakes a game is designed to return to players over a very large number of spins. House edge is the same figure from the other direction: a 96% RTP is a 4% house edge, and neither number is a prediction about your afternoon.
The word doing the heavy lifting is total. RTP is calculated across millions of spins, and variance across a few hundred spins swamps it completely. A high-volatility slot with 96% RTP can run cold for a thousand spins and still be behaving exactly as designed.
Volatility is the more useful number for choosing a game and the one operators publish least clearly. Low volatility means frequent small returns, high volatility means long droughts punctuated by occasional large hits, and the same RTP can sit behind either experience.
Some titles ship with multiple RTP configurations and the operator chooses which to run, so the same game can return 96% at one site and 94% at another. Where a game’s information panel shows the figure, it is worth checking rather than assuming.
The practical takeaway is that RTP is useful for comparing games and useless for predicting sessions, which is the opposite of how it is usually marketed.