Table 1.

Characteristics of included studies

Feature	Category	Number of studies
Type of study	Qualitative	19
	Quantitative	41
	Mixed methods	11
Study design	Randomised controlled trial	0
	Controlled experimental study	1
	Randomised factoral study	6
	Uncontrolled pre–post study	3
	Cohort study	1
	Cross-sectional study	35
	Unclear or other observational study design	28
Setting	UK	10
	US	30
	Rest of the world, multinational, or unclear	32
Sample size (individuals or organisations such as general practices)	1–100	32
	101–1000	21
	>1001	17
	Unclear	2
Participants	Patients or the general public only	42
	Clinicians and/or healthcare staff only	13
	Patients, clinicians, and/or healthcare staff	16
	Stakeholder groups	1
Mode of test communication	Online (including patient portals and electronic health records)	29