Table 2.

Descriptive statistics of measures used in the analysis (n = 1,947)

Construct	Original items	Range	Median	Mean	Standard deviation	Missing values
Attitudes toward surveys and research (H1.6)	QA9a-e	0–10	7.4	7.3	1.6	20
Security concern research app (H2.1)	QA14c	0–10	6.7	7.1	2.9	16
General privacy concern (H2.1)	QA12	0–10	6.7	5.6	2.4	2
No. perceived privacy violations offline (H2.1)	QA13a-d	0–4	1	1.2	1.3	0
No. perceived privacy violations online (H2.1)	QA13e-g	0–3	3	2.2	1.2	0
Trust data not shared by research organizations (H2.2)	QA10a-c	0–10	6.7	6.8	2.1	22
Trust data not shared by other organizations (H2.2)	QA10d,g,e,h	0–10	3.3	3.9	2.3	16
Smartphone skills (H2.3)	QA8	0–10	7.5	7.4	2.4	2
No. of devices (H2.4)	QA4a-e	1–5	3	3.1	0.9	0
Frequency of smartphone use (H2.4)	QA6	0–10	10	9.0	2.1	4
No. of smartphone activities (H2.4)	QA7a-l	0–12	9	8.4	3.0	0
		Invited, not downloaded	Never invited	Downloaded		Missing values
Experience with research apps (H2.4)	QB13,14	22.8%	62.8%	14.3%		7
		Less than 30 years	30–49 years	50 years and older		Missing values
Age	QB16	24.3%	50.3%	25.4%		4
		Female	Male			Missing values
Gender	QB15	47.0%	53.0%			6
		w/ HS degree	w/o HS degree			Missing values
Education	QB18	50.5%	49.5%			17