Table 3. Intraclass correlations between Fitbit and Actigraph and between devices and direct observations.

	ICC Actigraph vs direct observation			ICC Fitbit vs direct observation			ICC Fitbit vs Actigraph
	Average ICC	(95% CI)	P	Average ICC	(95% CI)	p	Average ICC	(95% CI)	p
Walking step count
First measures	0.67	(-0.23, 0.90)	<0.001	0.11	(-0.48, 0.55)	0.353	0.09	(-0.23, 0.43)	0.298
Second measures	0.75	(0.29, 0.91)	0.001	0.00	(-0.29, 0.37)	0.503	0.16	(-0.17, 0.50)	0.097
Average of measures	0.73	(-0.14, 0.91)	<0.001	0.05	(-0.30, 0.42)	0.390	0.10	(-0.15, 0.39)	0.195
Incline walking step count
First measures	0.75	(-0.17, 0.93)	<0.001	0.07	(-0.82, 0.57)	0.421	-0.06	(-0.66, 0.42)	0.583
Second measures	0.71	(0.31, 0.88)	0.002	0.19	(-0.58, 0.63)	0.281	0.21	(-0.33, 0.60)	0.202
Average of measures	0.74	(0.07, 0.91)	<0.001	0.11	(-0.58, 0.56)	0.356	0.02	(-0.45, 0.43)	0.467
Jogging step count
First measures	0.57	(-0.20, 0.84)	0.001	0.40	(-0.39, 0.74)	0.116	0.58	(0.08, 0.81)	0.008
Second measures	0.35	(-0.25, 0.71)	0.035	0.11	(-1.22, 0.65)	0.399	0.38	(-0.34, 0.73)	0.116
Average of measures	0.46	(-0.23, 0.78)	0.005	0.34	(-0.41, 0.71)	0.145	0.52	(-0.01, 0.78)	0.018
Stair stepping
First measures	0.18	(-1.01, 0.66)	0.329	-0.06	(-1.63, 0.56)	0.553	0.69	(0.28, 0.86)	0.004
Second measures	0.53	(-0.10, 0.81)	0.041	0.51	(-0.32, 0.81)	0.077	0.43	(-0.26, 0.75)	0.085
Average of measures	0.42	(-0.36, 0.75)	0.104	0.01	(-1.48, 0.59)	0.491	0.72	(0.38, 0.88)	0.001

CI: confidence interval, ICC: Intraclass correlation