Valve Closes Loophole Used to Create Incredibly Accurate Steam Video Game Sales Report

Not before we got a peek at the best-selling games on Steam.

News by Matt Kim, .

Earlier this year Valve created new privacy measures that essentially locked out third-parties from viewing data that would let them map sales data of games on Steam. But a loophole in Steam's data from earlier this week might have created the most accurate snapshot of video game player count on the platform to date. Too bad Valve closed it.

A leak in Valve's API allowed third-party developers to measure the number of players on any given game sold through Steam thanks to the way Steam Achievements worked. The End is Nigh developer Tyler Glaiel discovered a way to use those figures to track game sales thanks to the fact that the Steam API tracked Achievements to the incredibly precise 16 decimal place. The Steam website by contrast only rounds the data to two decimal places.

The extra precision let Glaiel reverse-engineer the number of players on a given game through Achievements, and thereby an accurate sales report of the game.

Sample of the Steam best sellers. Source: Ars Technica

While Valve closed the leak eventually, it wasn't before Ars Technica was able to publish a list of the 1,000 best-selling games on Steam thanks to Glaiel's method which Steam Spy developer Sergey Galyonkin then used with his Steam Spy machine learning algorithm. The combined effort created a CSV file with sales data for every game sold on the platform.

In April Valve announced new privacy changes that effectively killed sale trackers like Steam Spy from correctly collecting accurate sales data. Developers, especially smaller devs, relied on services like Steam Spy's to help gauge interest in their games and attract investors. Valve's changes could have been a result of European GDPR rules which put greater protection on privacy, but the backlash from the development community was strong nonetheless.

Now that this new source of data has also been closed, it will probably be a while before we can get accurate sales data from Steam again.

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  • Avatar for SatelliteOfLove #1 SatelliteOfLove 4 months ago
    How else will I shame and berate supposed lovers of refined members of certain genres to purchase the hidden classics without hard data?
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  • Avatar for Funny_Colour_Blue #2 Funny_Colour_Blue 4 months ago
    Woa, Terraria is a neat surprise on this list. I might just grab that for steam and wii u, along with a vita purchase I made years ago. I've never sat down and actually played that game. All I'd basically do, whenever a game would start is dig a whole to the centre of the earth - and just try to figure out ways of how to get to the centre of the earth faster/safer.

    ...I dunno, I'm weird.Edited July 2018 by Funny_Colour_Blue
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  • Avatar for docexe #3 docexe 4 months ago
    If I understood it well, the report at Ars Technica doesn’t contain the exact number of sales, but rather the number of people who have played a game enough time to get an achievement. Granted, it’s still probably the closest approximation we will ever have to hard sales on Steam and it’s probably a more useful metric for developers than if it included the number of people who bought a game because they saw it at discount during one of the seasonal sales and never even bothered to start it.

    A bit fascinating how so many of the multimillion sellers are relatively recent games and the usual suspects (Team Fortress 2, Skyrim, etc.). Makes you realize how much the PC market has grown in recent years.
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  • Avatar for Dikobrazo #4 Dikobrazo 3 months ago
    I was also pleased with the list of Terraria game. But I play Terraria online - it has many surprises, and among them, perhaps, the most important is the meeting with different opponents. The most common are zombies and slugs.
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