No big updates this week. Still cranking away at features I’ve brought up in the past.
Instead, here are some musings of mine on using data to look at playlist health.
Playlist Health
Here are two ways to look at Playlist health that I think are useful.
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Can players find matches.
This is the simplest one. If players can’t even find matches in a playlist, it’s definitely time for some form of maintenance. -
Can players find good matches.
In some cases, it’s not just whether we have enough players playing to make matches in those playlists, it’s whether we have enough players to make matches that are fair. Playlists tend to struggle as their level of fairness decreases.
One simple measure of a single match’s UN-fairness is how predictable its outcome is. If it’s obvious beforehand that Blue team will win, then the match isn’t that fair, it’s stacked in favor of the Blue team.
If most of the matches on a playlist have this problem — that one team is consistently more likely to win—then the entire playlist isn’t that fair, and a candidate for maintenance.
One value that is good at measuring predictability is how often the team with the highest MMR (skill rating) wins a match. Our skill system is pretty good at finding play skill, so it should be good at predicting match outcomes if the skill gap is too wide.
A perfectly fair playlist would be all matches where the team with the highest MMR wins only 50% (half) of the time. A playlist becomes less and less fair as the accuracy of the skill system at predicting that outcome increases. A playlist where we can predict the winning team correctly, e.g., 75% of the time is not a fair playlist.
This amount can vary greatly depending on the game modes in the playlist and its population. Different game modes have different levels of sensitivity to the skill gap.
If a game mode is less sensitive to a wide skill gap, it can support a smaller population and still have fair matchmaking. Playlists with modes like that are easy to maintain.
On the other hand, a game mode that is sensitive to the skill gap needs a larger population to provide the same quality of matchmaking and can fall under scrutiny even though it may seem to have plenty of players. Playlists with modes like that are harder to maintain, and may require the occasional “tough call” to keep the rest of the ecosystem healthy without falling below a reasonable quality bar.
Hopefully some fun thoughts for this week.
