Table 2.

Data extracted at stage four

Data extracted	Description1
Instrument development	Methods used to generate items (e.g., items derived from existing instruments; new items generated from data from interviews or comprehensive review of theory)
	Methods used to refine instrument
Administration & scoring	Method of administration (e.g., self-administered, facilitated)
	Feasibility of administration (e.g., researcher time, resources)
	Acceptability to respondents (e.g., views on burden and complexity)
	Methods of scoring and analysis
Measurement properties	Methods and findings of assessments of:
	Content validity (e.g., clear description of content domain and theoretical basis, expert assessment of items for relevance and comprehensiveness)
	Construct validity
	- Instrument structure (e.g., using factor analytic methods)
	- Hypothesis testing (e.g., whether scores on the instrument converge with measures of theoretically related variables, discriminate between groups, predict relevant outcomes)
	Reliability (e.g., internal consistency, stability over time, inter-rater)
	Responsiveness
Other assessments	Interpretability (potential for ceiling and floor effects; guidance on what constitutes an important change or difference in scale scores)
	Generalizability (sampling methods, description of sample, and response rate reported)

¹ Definitions and further explanation of the extracted measurement properties are provided in Additional file 3.