Since Pokémon Go's launch last summer, there have been plenty of anecdotal news reports and social media mentions of players being hurt or even killed while playing the game. A new study from Purdue University, though, uses detailed local traffic accident reports to suggest that Pokémon Go caused a marked increase in vehicular damage, injuries, and even deaths due to people playing the game while driving.

In the provocatively titled "Death by Pokémon Go" (which has been shared online but has yet to be peer-reviewed), Purdue professors Mara Faccio and John J. McConnell studied nearly 12,000 accident reports in Tippecanoe County, Indiana, in the months before and after Pokémon Go's July 6, 2016 launch. The authors then cross-referenced those reports with the locations of Pokéstops in the county (where players visit frequently to obtain necessary in-game items) to determine whether the introduction of a Pokéstop correlated with an increase in accident frequency, relative to intersections that didn't have them.

Getting at causation

While the incidence of traffic accidents increased across the county after Pokémon Go's introduction, that increase was a statistically significant 26.5 percent greater at intersections within 100 meters of a Pokéstop, compared to those farther away. All told, across the county, the authors estimate 134 extra accidents occurred near Pokéstops in the 148-day period immediately after the game came out, compared to the baseline where those Pokéstops didn't exist. That adds up to nearly $500,000 in vehicle damage, 31 additional injuries, and two additional deaths across the county, based on extrapolation from the accident reports.

The study uses a regression model to account for potential confounding variables like school breaks and inclement weather, which could cause variation separate from Pokémon Go. The model also compares Pokéstops to Pokégyms (where it was nearly impossible to play while driving) to account for the possibility that generally increased traffic to Pokémon Go locations was leading to more accidents, even among drivers who stopped and parked before playing. In all cases, though, being able to compare to intersections without a Pokéstop and to the same dates the year before, helped provide natural control variables for the study.

Is this a big problem?

Other data points also suggest Pokémon Go as the main culprit in the shift. For instance, the relative increase in accidents at these locations tracked closely with the reported Daily Active Users for the game worldwide, which peaked in July and fell steadily through November (the last month in the study). The effect is also measurably reduced as you increase the observed distance from a Pokéstop between 50 and 500 meters. And the traffic reports themselves show a disproportionate increase in "distracted driver" as the listed cause for intersections near Pokéstops after the game's release (though a limited sample size and problems with self-reported causes complicate this last data point).

While the authors warn that extrapolating one county's results to the entire country is "speculative," the totals here suggest more than 145,000 additional crashes, 29,000 additional injuries, and 250 additional deaths could have been caused by playing Pokémon Go while driving in the five-month period following the game's release. And that doesn't even account for distracted players getting into accidents farther away from Pokéstops while searching for wild Pokémon or simply looking for unknown locations.

Developer Niantic hasn't ignored Pokémon Go's potential for causing distracted driving. Starting last August, an update to the game warned players in fast-moving vehicles that "You’re going too fast! Pokémon Go should not be played while driving," and asked them to confirm they were a passenger before continuing. Then, starting last November, Niantic began making the game virtually unplayable in a fast-moving vehicle, even for passengers.

That, combined with the generally reduced player numbers seen since Pokémon Go's release, suggest the game's current effect on vehicular carnage may be reduced from that shown in the study. Still, with Niantic's Harry Potter-themed follow-up to Pokémon Go in the works, and with phone-related distracted driving becoming an increasing problem across the country , this is definitely a problem for mobile AR game developers and players to keep an eye on.