Skip to main content
. 2021 Mar 15;23(3):e23984. doi: 10.2196/23984

Table 2.

Comparison of 6 weeks of digital phenotyping data before (from 45 days before to 3 days before) and after (from 3 days after to 45 days after) the start of Singapore’s Circuit Breaker on April 7, 2020.

Feature name 6-week before CBa starts, mean (SD) 6-week after CB starts, mean (SD) P value (paired t test) P value (Wilcoxon signed rank test)
Smartphone features

accel_L_std (L: length of the accel. vector) 0.526 (0.325) 0.370 (0.345) <.001 <.001

accel_ddt_max (ddt: time derivative) 0.00807 (0.0044) 0.00551 (0.0041) .005 <.001

ambientLight.hourly_max_log1p_lux 2.538 (0.721) 2.190 (0.587) .001 .001

callLog_Incoming Call 0.533 (0.835) 0.288 (0.560) .001 <.001

gps-mobility_Hometime / mins 1111 (292) 1328 (143) <.001 <.001

gps-mobility_SigLocsVisited 1.354 (0.429) 1.220 (0.288) .01 .02

powerState.hourly_n_screen_on 6.716 (2.77) 5.180 (2.44) .008 <.01

tapsLog.daily_n_unique_apps 16.10 (4.54) 14.24 (4.47) .04 .04

tapsLog.daily_n_taps_in_entertainment 293.9 (259) 378.3 (365) .07 .05
Wrist-wearable features

steps.daily_n_steps 3921 (2435) 2400 (1807) .001 <.001

steps.daily_n_mins_walk 113.8 (53.23) 79.78 (54.24) <.001 <.001

heart.daily_HR_mean 82.89 (10.48) 80.35 (9.04) .10 .03

heart.daily_HR_min 56.08 (6.85) 55.74 (7.23) .77 .26

sleep_total_hrs 9.196 (1.94) 8.727 (1.98) .31 .096

sleep_mean_efficiency 93.27 (3.08) 92.39 (3.38) .04 .009

aCB: circuit breaker.