# RTP and volatility: what a percentage cannot tell you

An average return is not a session forecast or a promise about a specific game configuration.

By Casimo Research. Explanatory guide; not a first-person casino test.

## A long-run model, not a personal result

Return to player is an expectation under a game’s rules and configuration. A short session can differ greatly from that expectation. Knowing an average alone does not identify the distribution of outcomes.

## Volatility labels are incomplete

Low, medium and high are coarse descriptors, not full mathematical specifications. A credible simulation of a real slot needs more than a label and an RTP percentage.

## What Variance Lab does

Casimo uses a deliberately simple, stated toy distribution to illustrate uncertainty and independent trials. It is not a reconstruction of any operator’s slot or a prediction of a redemption.

## Sources
- [UK Gambling Commission · return to player guidance](https://www.gamblingcommission.gov.uk/public-and-players/guide/page/how-to-calculate-return-to-player-rtp)

Canonical: https://casimo.org/learn/rtp-and-volatility-explained