Valve Shuts Down New Way of Estimating Game Sales On Steam (arstechnica.com)

A recently discovered hole in Valve's API allowed observers to generate extremely precise and publicly accessible data for the total number of players for thousands of Steam games. While Valve has now closed this inadvertent data leak, Ars can still provide the data it revealed as a historical record of the aggregate popularity of a large portion of the Steam library. From the report: The new data derivation method, as ably explained in a Medium post from The End Is Nigh developer Tyler Glaiel, centers on the percentage of players who have accomplished developer-defined Achievements associated with many games on the service. On the Steam web site, that data appears rounded to two decimal places. In the Steam API, however, the Achievement percentages were, until recently, provided to an extremely precise 16 decimal places.

This added precision means that many Achievement percentages can only be factored into specific whole numbers. (This is useful since each game's player count must be a whole number.) With multiple Achievements to check against, it's possible to find a common denominator that works for all the percentages with high reliability. This process allows for extremely accurate reverse engineering of the denominator representing the total player base for an Achievement percentage. As Glaiel points out, for instance, an Achievement earned by 0.012782207690179348 percent of players on his game translates precisely to 8 players out of 62,587 without any rounding necessary (once some vagaries of floating point representation are ironed out). Ars has shared the Achievement-derived player numbers in their report; there's also a handy CSV file. Some of the titles with the most total unique players include Team Fortress 2 (50,191,347 player estimate), Counter-Strike: Global Offensive (46,305,966 player estimate), PLAYERUNKNOWN'S BATTLEGROUNDS (36,604,134 player estimate), Unturned (27,381,399 player estimate), and Left 4 Dead 2 (23,143,723 player estimate).

Comments

Re:The question everyone's asking

[The Raven]

It's a zombie survival game, cartoonish graphics but well designed, in the style of the DayZ mod. Free to play, with $5 buy in to gold servers (essentially a fee to avoid more rampant cheating) and cosmetics.

Not particularly amazing or awe inspiring, but well made and with a huge young-player following. Parents don't ban it because it's so non-threatening looking with it's lo-fi cartoonish graphics, though the gameplay is the usual find or craft guns, kill zombies, and kill your fellow humans if you think they looked at you funny.

The interesting thing is that it's pretty much the work of a single dev... a kid who started work on it at around 14 or 15, and who I suspect is a millionaire already, though I don't think he can drink yet. What's the drinking age in Canada?

Re:Factors?

[Calydor]

As the summary said, when you have multiple achievements with different values, you very quickly come to a point where there is only one X that fits all the equations.

If another achievement has been completed by 127 players, and the most common one is done by 59,993 players, you quickly run out of possibilities. Sure, there MAY be another result in the billions of players, but that's like GPS - all GPS calculations have TWO solutions to the equation, but one solution is on the planet's surface while the other is in outer space.

Re:Not so rare after all

[hairyfeet]

Exactly, I have nearly 200 games in my Steam library, I've played....maybe 12. Most of them I've downloaded once, backed them up to my external drive, and then promptly forgot about them because I don't have the hours to play them all.

This is the problem game devs are gonna find with more and more playing MMOs as once you've sunk some serious time into a MMO game you like? You have a limited amount of hours in the day and many will just go play the game they have already invested in.I keep buying games because I'll see something that looks interesting in a Humble Bundle or on a Steam sale but when it comes time to actually play it? i just end up going back to my MMO.