A new study published in the International Journal of Performance Analysis in Sport officially confirms what we (probably) already knew: work emails and phone calls are ruining our golf game and costing us strokes. A group of researchers from Stellenbosch University in South Africa studied 186 recreational golfers at five different clubs and came to the unequivocal conclusion that smartphone use in the workplace has a “small negative impact on performance.”

“We found that golfers’ performance was not affected when they used their phone for personal purposes, such as checking social media feeds or responding to messages. However, when they read work-related emails or took work-related calls, their performance dropped,” said lead researcher Dr. Daniël le Roux. Postgraduate students Lise Carstens, Cole Walburgh and Christen Werth were also key participants in compiling this study.

“Our study highlights the double-edged nature of smartphones on the golf course,” writes le Roux. “While they provide the convenience of staying connected, their interference can impair concentration and performance and ultimately make the game less enjoyable.”

The study even references a 2015 article by Alan Pittman in Golf Digest about smartphone use and its downsides. After surveying 233,000 golfers, GD found that more than 40 percent of golfers felt the need to check their phone every few holes. It’s safe to assume that this number has increased over the past nine years.

The reason work-related smartphone use hurts your game more than general texting and browsing, the study found, is due to “cognitive switching between swing routines and work-related problems.” These switches can interfere with pre-swing routines, preventing golfers from completely forgetting their work problems. This, in turn, throws them off track when it comes to their actual golf game.

“Mind wandering during these routines has been shown to impair performance,” the study says. “Such residual effects may be particularly strong when smartphone interaction between recordings involves work-related communication and the configuration of complex task sets in working memory. For example, a work-related call from a colleague about a complicated business problem may be more distracting (and detrimental to performance) than a casual instant message from a friend.”

It’s also important to reflect after your shot to see what worked (or, in many cases, what didn’t). This becomes more difficult when you still have random external ailments floating around in your head. The study results make it clear that you should be thinking about golfing finer points like “course layout, ball lie, pin location, wind speed/direction, technical changes since the last similar shot or situation” rather than answering a question on Slack after the round or scheduling a meeting in Outlook.

While this isn’t news, it’s always good to have some science to back it up when you tell your boss that you need to play golf for four to five hours straight. Just send this study to your colleagues while they’re on the golf course to keep work to a minimum and improve your game. We’re sure they’ll understand.