Fig. 1.

Percentage of the mean absolute difference between two estimates with an increasing number of days analyzed for the parameters SE (sleep efficiency), FI (fragmentation index), SOL (sleep onset latency), WASO (wake after sleep onset), and TST (total sleep time). For the number of days analyzed, “1” refers to day 1 vs. day 15, “2” refers to days 1–2 vs. days 15–16, “3” refers to days 1–3 vs. days 15–17, etc. The mean absolute differences between a 7-day and a 14-day analyzed set were statistically compared, and the results are shown in Table 2.