We all can use some level of sleep optimization. One way to improve the quality of your sleep is by tracking sleep efficiency. This is the ratio of total time spent asleep versus the total amount of time you were in bed. Factors affecting your sleep efficiency score can be the amount of time it takes you to fall asleep when you first lay down (sleep latency) or the number of times you wake up during the night.
The key question is: what is a good sleep efficiency score? According to the Journal of Clinical Sleep Medicine, sleep efficiency scores above 85% are considered normal. Scores above 90% are considered very good, unless you are not waking up feeling fully refreshed. If that is the case, it might be an indicator that you are not sleeping for long enough. And if your score is consistently below 85%, it might be an indicator of insomnia.
If you tend to lay in bed and do other things prior to going to sleep (e.g., watching TV or reading), make sure you exclude that time from your sleep efficiency calculation, otherwise your ratio might be artificially low.