Table 2.

Quality assessment of quantitative studies included in systematic review

Studies	Bang et al. 14	Pérez et al. 15	Saullo et al. 20	Mukattash et al. 16	Mukattash et al. 17	Lenk et al. 13	Mukattash et al. 12	Stewart et al. 21	McLay et al. 18	Ekins‐Daukes et al. 19
Quality assessment domains
Research question and design
a) Was there a clear research question, and was this important and sensible?	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓
b) Was a questionnaire the most appropriate research design for this question?	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓
Sampling
c) Was the sampling frame sufficiently large and representative?	✓	✓	?	✓	✓	✗	✓	✓	?	?
d) Did all participants in the sample understand what was required of them, and did they attribute the same meaning to the terms in the questionnaire?	✓	✓	?	?	?	?	✓	?	✓	?
Instrument
e) Were the claims for reliability and validity made, and are these justified?	✓	✗	✗	✓	✓	✗	✓	✓	✗	✗
f) Did the questions cover all relevant aspects of the problem in a non‐threatening and non‐directive way?	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓
g) Were open‐ended (qualitative) and closed‐ended (quantitative) questions used appropriately?	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓
h) Was a pilot version administered to participants representative of those in the sampling frame, and the instrument modified accordingly?	?	✓	✗	✓	✓	✓	✓	✓	✗	✓
Response
i) Have non‐responders been accounted for?	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓
Coding and analysis
j) Was the analysis appropriate (e.g. statistical analysis for quantitative answers, qualitative analysis for open‐ended questions) and were the correct techniques used?	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓
k) Were adequate measures in place to maintain accuracy of data?	✓	✓	?	✓	✓	✓	✓	✓	✓	✓
Presentation of results
l) Have all relevant results (‘significant’ and ‘non‐significant’) been reported?	✓	✓	?	✓	✓	✓	✓	✓	✓	✓
m) Is there any evidence of ‘data dredging’ (i.e. analyses that were not ‘hypothesis driven’)?	✗	✗	✗	✗	✗	✗	✗	✗	✗	✗
Bias
n) Is there evidence of any other bias (e.g. funding bias)?	?	✓	?	✓	✓	✓	?	✓	?	?

✓ = yes;

× = no;

NR = not reported;

? = unclear