Table 7.

Percentage error, mean difference, and 95% limits of agreement between total activity measured by Actigraph GT3x and activity minutes from each monitor.

Device	n	% error, Mediana	% error, Minimum, maximum (range)	≥ 5% error, n (%)	≥ 10% error, n (%)	≥ 25% error, n (%)	p-valueb
Total activity
Letscom	17	52.9	5.6, 65.1 (59.6)	17 (100)	16 (94.1)	15 (88.2)	<0.001
Fitbit Alta	18	100.0	−38.7, 100.0 (138.7)	18 (100)	18 (100)	18 (100)	<0.001
Garmin Vivofit 4	18	100.0	100.0, 100.0 (0.0)	18 (100)	18 (100)	18 (100)	<0.001
Light physical activity
Letscom	17	48.6	5.3, 63.3 (58.1)	17 (100)	15 (88.2)	14 (82.3)	<0.001
Fitbit Alta	18	100.0	−38.7, 100.0 (138.7)	18 (100)	18 (100)	18 (100)	<0.001
Garmin Vivofit 4	18	100.0	100.0, 100.0 (0.0)	18 (100)	18 (100)	18 (100)	<0.001
Moderate to vigorous physical activityc
Letscom		n/a	n/a	n/a	n/a	n/a	<0.001
Fitbit Alta		n/a	n/a	n/a	n/a	n/a	0.052
Garmin Vivofit 4		n/a	n/a	n/a	n/a	n/a	<0.001

^a Positive value indicates the device underestimates steps in comparison to Actigraph GT3x

^bp value obtained from Wilcoxon signed rank test comparing activity time from each device to Actigraph GT3X.

^cUnable to calculate percentage error because some people had 0 minutes of moderate-to-vigorous physical activity as measured by the Actigraph GT3X.