Questionnaires have been helpful, but a precise characterization of the impact societal pressures have on sleep remains out of reach. Smartphones have enabled researchers to change all of that. In 2014, a research group at the University of Michigan created and released an app they called ENTRAIN. The app received details about the usual sleep times, the home time zone, and the typical lighting experienced by the user. Users were able to transmit their data to the servers of the researchers, who then got a wealth of information and published about it in Science Advances.
Daniel Forger, of the Department of Mathematics at University of Michigan and one of the authors of the study, commented to the BBC, "Society is pushing us to stay up late, our clocks are trying to get us up earlier and in the middle the amount of sleep is being sacrificed; that's what we think is going on in global sleep crisis.” He continued, "If you look at countries that are really getting less sleep then I'd spend less time worrying about alarm clocks and more about what people are doing at night - are they having big dinners at 22:00 or expected to go back to the office?"
It was also reported that those who spent the most time in natural sunlight also tended to go to bed earlier. Working overnight shifts has been linked to a host of serious health problems, and getting to the cause of that is very important for public health.
Importantly, the researchers have demonstrated that using an app for reliable data collection is possible, which could have broad, positive implications for public health research.
Sources: Science Advances, BBC