Ideally, the app could provide a reading down to the minute. Accuracy and precision: We looked for apps that could give reasonably good readings for when we fell asleep, when we woke, how often we woke up during the night, and when we entered various sleep stages.“But when a sleep tracker says you’ve had too little deep sleep, most people aren’t sure what to do with that.” We looked for trackers that gave advice or put the data in context, reminding people to get to bed more consistently, for instance, or letting them know when they may be sleep deprived. “If a pedometer registers 1,400 steps at 2 p.m., you know exactly what you need to do-go out for a walk,” Winter said. Actionable advice: Without offering solid direction as to how you can get better sleep, these apps are just platforms for spitting out graphs.Clearly labeled x- and y-axes and reports in everyday English are a huge help at 5:30 in the morning. Ease of interpretation: Multicolored graphs look impressive, but they’re useless if they require a doctorate in statistical analysis to understand.We also preferred apps that allowed us to set our phone on a nightstand as opposed to on the bed.