19. How Many Players Are Needed?
A Playtesting Primer
The main purpose of a usability playtest is to uncover what sorts of friction points might hinder a player and how impactful are those issues to the player experience. We are not particularly interested in how many people experienced an issue, although that might be considered, but rather we’re more interested in what the issue is and how severe was the issue they experienced. Usability playtests are not a quantitative method, we’re not reporting how many players had an issue, but we will be reporting the presence of an issue, and how impactful we think that issue is to the player experience.
With this in mind, when it comes to figuring out how many players you need to recruit for a usability playtest, a commonly used number is 6 players for each of your target audience types (cohorts). For example, if you think your game only has one main type of player, then recruiting 6 players of this audience type for each playtest is enough to find the majority of issues in your game. If you feel that you have two somewhat distinct audience types, then you would need to recruit 6 players per cohort, and see how players in each group perform. The commonly used choice of 6 players is not a fixed rule, but rather a trade-off between time spent on research and results obtained. It’s the law of diminishing returns in practice, sure, you can playtest with more players, but there is probably little to gain from doing so, most of the main issues will already have been found. You are more likely to find and remove more issues in your game by increasing the number of usability tests across development rather than increasing the number of players per individual test.
It can’t be stressed enough how important it is to recruit suitable players for playtesting, if you are selecting inappropriate players, then you’ll very likely get misleading results.
Key Takeaway
Usability playtesting is about detecting friction points in your game. The number of players to use is not set in stone, but 6 players per cohort is a reasonable trade-off between time invested and issues uncovered.