Late-night tweeting is associated with worse performance

In what is one of the least surprising research results of 2018, a new article in the journal Sleep Health (sorry I don't see an ungated version) by Jason Jones (Stony Brook University) and co-authors looks at the relationship between late-night activity on Twitter and next-day game performance of NBA players. Specifically, they had data from 112 players from 2009 and 2016, and limited their analysis to East Coast teams playing on the East Coast, and West Coast teams playing on the West Coast (to avoid any jetlag effects). They found that:

[f]ollowing late-night tweeting, players contributed fewer points and rebounds. We estimate that players score 1.14 fewer points (95% confidence interval [CI]: 0.56-1.73) following a late-night tweet. Similarly, we estimate that players secure 0.49 fewer rebound [sic] (CI: 0.25-0.74). They also commit fewer turnovers and fouls in games following a late-night tweet. We estimate the differences to be 0.15 fewer turnover (CI: 0.06-0.025) and 0.22 fewer foul (CI: 0.12-0.33). These results are consistent with a hypothesis that players are less active in a game following a late-night tweet but not that the general quality of their play necessarily deteriorates.

We noted that, on average, players spent 2 fewer minutes on the court following late-night tweeting (no late-night tweeting: 24.8 minutes, late-night tweeting: 22.8 minutes).

Presumably, coaches realise that the sleep-deprived players are not playing at their usual standard, so the players spend more time on the bench rather than on the court. That explains some of the other effects (fewer points, rebounds, turnovers, and fouls), but Jones et al. also found that shooting percentage was lower after late-night tweeting (and shooting percentage shouldn't be affected by the number of minutes on court). Interestingly:

...infrequent late-night tweeters who late-night tweeted before a game scored significantly fewer points; made a lower percentage of shots; and also contributed fewer rebounds, turnovers, and fouls as compared to nights when they did not late-night tweet. By contrast, these effects were not seen among frequent late-night tweeters...

So, those players who were regular late-night tweeters were less affected than those whose late-night tweeting was uncommon. Of course, the results don't tell us for sure whether those who regularly sleep less are less affected by lost sleep, or why. Late-night tweeting is an imperfect proxy for lack of sleep (at least in part because those not engaging in late-night tweeting need not necessarily be sleeping). However, the results are suggestive that late-night tweeting is associated with worse performance. Which should give us pause when we think about people in positions of power who have made a regular habit of tweeting at odd times.

[HT: Marginal Revolution]