Collecting detailed sleep data from crew is often a part of building evidence for a safety business case but also a neccessity when improving upon fatigue models such as the Boeing Alertness Model. This type of data has traditionally been collected using both manually recorded sleep/wake diaries and so-called 'actiwatches' - a medical grade instrument containing accelerometers registering movement. The movement data is later interpreted by software algorithms into likely sleep/wake periods for the person wearing the device. The drawback with this, which has limited the amount of collected data, has been the extensive logistics needed and the very costly devices.
It seems now, not surprisingly, that the fast development and high interest in wearable devices is quickly closing the capability gap between the older more expensive technology of actiwatches and modern low-cost fitness bands used by millions of people. A recent publication comparing the technologies arrived at this conclusion: 'A consumer-grade wearable device can measure sleep duration just as well as a research actigraph. However, sleep staging would benefit from further refinement before these methods can be reliably used for adolescents.'
With more of these validation studies coming up, which really has been the limiting factor - not the technology itself, it is likely that we can soon capitalize from much larger data sets. We can then improve crew rosters even further when fatigue models are used proactively to influence the sequencing of activities for crew. Happy days indeed. Please find a link to the abstract here. (The full paper is behind a paywall.)