How is the mean sleep latency calculated?

The mean sleep latency is calculated by taking the sum of all sleep onset latencies from multiple opportunities to nap and dividing it by the number of naps taken. Sleep latency refers to the amount of time it takes an individual to transition from full wakefulness to sleep. By averaging the sleep latencies from several naps, this calculation provides an effective measure of how quickly a person falls asleep, which can be useful in assessing sleep disorders or the overall sleepiness of a patient.

This method of calculation allows clinicians to gain insight into a person's propensity to fall asleep in a nap context, rather than using other metrics that may not be relevant. For example, calculating an average based solely on wake times or total sleep over nights does not provide the specific information needed to assess sleep latency effectively.