APM is inflated in shorter games due to time before the horn

[TheGuywithTheHat]

If a game is registered as having a duration of 90, that means it ended 1:30 after the horn. However, a normal game starts at -1:30, not 0:00, so the actual time each players spends in the game is double the "official" duration value. This causes an issue with APM calculations (and likely many other calculations as well, but APM is the most noticeable), because all actions taken in the 90 seconds of pregame time are still counted. If someone clicks once a second in that "90 duration" game, they will have 180 clicks total. With the current calculation, this causes the APM to allegedly be 120, when in reality it was only 60. For examples, you can see my APM records page.

A fix isn't easy, because not all games have the same amount of pregame duration. Normal matches have 90 seconds, turbos have 60, others may or may not have different values. Also, if there were a fix implemented, it would have to be retroactively applied to all previous matches, so that there isn't a weird jump in the stats.

How can we fix this? Is it even worth trying?

[howardchung]

This is hard because an accurate measurement would require replay parsing and we don't do that for all matches. We could attempt to adjust duration based on game mode, but this also changes from time to time so it would probably not stay accurate between patches.

Another possibility is to drop actions from before 0:00, but that might not be accurate.

Most matches are long enough that this isn't an issue, but it's good to think about. . .