They employed 452 adults for a one-month data-entry job, which the authors say it's "a relatively cognitively-demanding task intended to be sensitive to sleep deprivation."
As a side note, the study also says that short afternoon naps increased productivity.
Because of a combination of health, family, and time zone issues, I sleep approximately 5 hours a night (6 or 7 on weekends, if I'm lucky). I also have a complex work environment where the ability to think quickly, have excellent recall, and make quick decisions is paramount (I manage two dev teams working on two very different code bases, facing very different challenges). The people I work with are often "the smartest person in the room" and notice slips and mistakes.
Anyway, I get by through a combination of sneaking naps, trying not to sabotage myself by eating/living poorly, and catching up when I can.
I suspect the people in this study do the same. They probably doze when on public transportation, or trying to get the kids to sleep, you'll lay down with them and sleep a little. These stolen moments add up. Also, learning to recognize the signs of mental fatigue - if you can't get rest, then, you have to slow down and double check everything, not get irritable, and defer major decisions.
I'm...extremely skeptical a generic "data entry job" is "high cognitive demand".
I can write new applications (atrociously) on basically no sleep, so I'm pretty skeptical "sit at this desk and enter these things" swings one way or the other (or even has much of an ability to quality check - at least the compiler will yell at me when I'm egregiously wrong).
I'd be far more interested if these people could be trusted to run heavy machinery on that schedule, or engage in a creative or hands on task like carpentry or welding. I suspect the results would be quite different.
I'm...extremely skeptical a generic "data entry job" is "high cognitive demand".
Same here. While writing the GP comment, I considered using that exact example as something that I wouldn't expect to be heavily impacted by moderate sleep deprivation.
I don't know how well it compares to a spanish siesta but the abstract ends with "In contrast, short afternoon naps at the workplace improved an overall index of outcomes by 0.12 standard deviations, with significant increases in productivity, psychological well-being, and cognition, but a decrease in work time."
As a side note, the study also says that short afternoon naps increased productivity.