Table 2.

Infant Sleep Characteristics (per 24 hours)

Measure	Method	NL	US	Difference	Effect Size (d)	Test Statistic	p
		Mean (SD) or Median (range)	Mean (SD) or Median (range)
Total Sleep (h)
	Diary	13.92 (1.54)	12.42 (1.96)	1.51	0.89	t = 2.03	.05
	Actigraph	13.63 (1.92)	11.96 (1.43)	1.67	1.00	t = 3.41	.001
Number of Sleep Episodes (n)
	Diary	4.31 (2–9)	3.38 (1–6)	0.00	-	z = −1.06	.29
	Actigraph	14.00 (5–22)	12.50 (4–30)	1.50	-	z = 1.00	.32
Longest Sleep Episode (h)
	Diary	10.58 (4.33–12.00)	8.83 (3.25–10.83)	1.75	-	z = 1.91	.06
	Actigraph	4.17 (2.28 – 6.85)	3.19 (1.03 – 7.57)	0.98	-	z = 1.16	.24
Longest Wake Episode (h)
	Diary	3.67 (2.25–10.75)	3.88 (2.83–9.25)	−0.21	-	z = −0.42	.67
	Actigraph	2.98 (0.97 – 5.97)	3.91 (2.08 – 6.50)	−0.93	-	z = −2.01	.04
Percent Night Sleep
	Diary	76 (6.9)	81 (7.2)	−4.5	0.64	t = 2.08	.05
	Actigraph	73.1 (46.1 – 87.1)	79.2 (53.4 – 98.1)	−6.1	-	z = −1.95	.05
Daytime sleep (h)
	actigraph	3.74 (1.29)	2.64 (1.33)	1.10	0.84	t = 2.86	.006
Nighttime sleep (h)
	actigraph	9.73 (6.92–11.17)	9.80 (4.88 – 11.28)	−0.07	-	z = −0.50	.61
Number daytime sleep episodes (raw)
	actigraph	5.5 (2 – 12)	4.0 (1 – 18)	1.5	-	z = 1.37	.17
Number daytime sleep episodes, smoothed 1 min
	actigraph	5.5 (2–12)	3.0 (1–16)	2.15	-	z = −2.01	.04
Average length of daytime episode (h)
	actigraph	0.70 (0.28 – 1.55)	0.56 (0.18 – 1.50)	0.14	-	z = −1.12	.26
Number nighttime sleep episodes
	actigraph	8.0 (3–16)	7.0 (2–16)	1.0	-	z = −0.12	.90
Average length of nighttime episode (h)
	actigraph	1.34 (0.53–3.49)	1.12 (0.41 – 4.83)	0.22	-	z = −.78	.43