Data Sources
Sleep duration data is compiled from multiple methodologically distinct sources. The primary dataset is the OECD Time Use Survey, which uses 24-hour time-use diaries — the gold standard in time-use research. Secondary data comes from the Sleep Cycle app (smartphone-based sleep tracking) and World Population Review (wearable/app aggregation).
Important Methodological Notes
OECD data measures "time allocated to sleep" from diary surveys (ages 15-64), which includes time in bed attempting to sleep. App/wearable data measures detected sleep states, which typically produces lower values. The two methodologies are not directly comparable — OECD values will consistently be higher than app-based values for the same country.
Survey years vary by country (1999–2022). Not all countries have data for all years or demographics.
Sources