A few months ago, I needed to head to A&E. My condition wasn’t serious enough to warrant calling an ambulance, but as a recent graduate living in London I don’t own a car: so I ended up getting an Uber. According to a new study from University of Kansas economist David Slusky and co-author Leon Moskatel, I’m not the only one who’s been in this situation.

The paper (which is currently undergoing peer-review) examines how ambulance use rates changed when Uber began operating in US cities, and looks at data from 2013 to 2015. During that period, the authors found that ambulance use rates declined by an average of 7% after Uber (specifically UberX) began operating in a city. They argue that this can be explained, at least in part, by low-risk patients substituting ambulances for Uber. If this is the case, ridesharing services are cutting healthcare costs for low-risk patients by reducing the need for expensive ambulances. More significantly, Uber and other ridesharing platforms would be freeing up ambulances for those who need them most: reducing their waiting times and potentially saving lives. Following this logic, some U.S. hospitals have considered formally partnering with ridesharing platforms for low-risk patients.

Although the study doesn’t compare cities that got Uber to cities that didn’t, the prospect of declining ambulance use being explained by regional trends is unlikely. The map below shows that Uber’s entry into major US cities was “reasonably randomly distributed across the country, with no obvious pattern by region, city area, or population”:

A more pressing objection to the study’s conclusions is that the Uber could reduce ambulance use via an entirely different mechanism - a reduction in DUIs and assaults. My colleague Sam Dumitriu has previously explored the evidence supporting this argument:

...the rate of vehicular accidents falls quite dramatically when Uber enters a city, with traffic fatalities declining by 16.6 per cent over a year. This can be explained by both a reduction in the number of people driving under the influence, as well as the fact that the people most likely to use Uber (i.e. millennials) are terrible drivers and anything that keeps them off the road is a good thing.

Second, [evidence suggests] declines in arrests for both assaults and disorderly conduct. This may be because Uber reduces passenger wait times, lowering the risk of someone being attacked while waiting for a cab.

However, ambulances dispatched to respond to assaults and DUI incidents are unlikely to make up the vast majority of ambulance use in America. It is unlikely that reductions in assaults and DUIs explain away most of the reduction in ambulance use once Uber enters a city. Either way, ridesharing services are potentially saving lives; this study is a valuable indication that Uber might be doing so in a completely different way.