Table 3:

Correlation between aggregate usage features and PHQ-9 scores.

		All		Depressed		Non-depressed
	Feature	r-value	p-value	r-value	p-value	r-value	p-value
iOS	Total duration	0.25	10−3	0.26	0.006	0.28	0.05
	Total number of sessions	0.27	10−4	0.28	0.003	0.31	0.03
	Total off-duration	−0.11	0.16	−0.06	0.49	−0.19	0.17
	Duration (morning)	−0.40	10−8	−0.27	0.004	−0.49	10−4
	Duration (afternoon)	−0.27	10−4	−0.35	10−4	−0.16	0.27
	Duration (night)	0.39	10−7	0.34	10−4	0.48	10−4
	Duration (midnight)	0.28	10−3	0.16	0.09	0.33	0.02
	Number of sessions (morning)	0.11	0.16	0.17	0.07	0.14	0.31
	Number of sessions (afternoon)	0.17	0.03	0.18	0.05	0.25	0.08
	Number of sessions (night)	0.36	10−6	0.36	10−5	0.37	0.007
	Number of sessions (midnight)	0.36	10−6	0.35	10−4	0.35	0.01
Android	Total duration	0.28	0.12	−0.47	0.03	0.62	0.06
	Total number of sessions	−0.04	0.84	−0.32	0.14	0.32	0.37
	Total off-duration	0.10	0.60	0.34	0.13	−0.21	0.56
	Duration (morning)	−0.11	0.56	0.01	0.95	−0.36	0.31
	Duration (afternoon)	−0.08	0.68	0.01	0.95	−0.38	0.28
	Duration (night)	−0.06	0.73	−0.19	0.40	0.31	0.39
	Duration (midnight)	0.32	0.08	0.23	0.31	0.56	0.09
	Number of sessions (morning)	−0.19	0.31	−0.32	0.14	−0.19	0.61
	Number of sessions (afternoon)	−0.21	0.26	−0.27	0.22	−0.28	0.44
	Number of sessions (night)	0.02	0.93	−0.33	0.14	0.43	0.21
	Number of sessions (midnight)	0.28	0.12	−0.13	0.56	0.50	0.14