Table 1

Methodological limitations of included studies using the CASP qualitative study tool

CASP criteria18	Was there a clear statement of the aims of the research?	Is a qualitative methodology appropriate?	Was the research design appropriate to address the aims of the research?	Was the recruitment strategy appropriate to the aims of the research?	Was the data collected in a way that addressed the research issue?	Has the relationship between researcher and participants been adequately considered?	Have ethical issues been taken into consideration?	Was the data analysis sufficiently rigorous?	Is there a clear statement of findings?	How valuable is the research?
Rivara et al 24	Yes	Yes	Yes	Unclear	No	No	No	No	No	The study had a small sample size. Data saturation and analysis methods were not properly described. There was discordance between the age in objective and eligibility criteria. Participant quotes to back up themes was sparsely presented.
Simpson et al 34	Yes	Yes	Yes	Yes	Yes	Unclear	Unclear	Unclear	Yes	Not much reported on analyses to decide on reliability, validity or reflexivity. However, the results discussed how the study contributed to determining parental differences between optimal child restraint use and the need for quantitative studies in the future. It was not clear why the ethics exempt status was given for this research.
Lee et al 25	Yes	Yes	Yes	Yes	No	Unclear	Yes	No	Yes	Data saturation was not mentioned. Not much detail about analysis methodology or results was presented and only a narrative report was provided with positionality and reflexivity remaining unclear.
Agran et al 26	Yes	Yes	Yes	Yes	Unclear	No	Yes	No	No	The study did not include much detail about data collection. Reflexivity and data saturation were not mentioned. Basic characteristics of the participants or quotes were not reported. However, the researcher briefly discussed the contribution the study in terms of implementation of laws.
Lennon27	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	The study was well conducted, and the researcher discussed the contribution it made in the larger context and the issue of generalisability, reliability and validity.
Medoff-Cooper and Tulman28	Unclear	Yes	Yes	Unclear	No	Unclear	Yes	No	Yes	The study abstract and main text aims were not the same—there was no clear statement of the aim of the research. There was no discussion on data saturation or reflexivity or other issues regarding reliability and validity of the data. Considering there were only two FGDs, it is not clear how valuable the research is to local context. The discussion did not adequately describe the specific contribution to the literature or what the implications of the study were other than the statement that there was need to conduct this study in larger groups.
Winston et al 21	Yes	Yes	Unclear	Yes	Unclear	No	Yes	Yes	Yes	The evaluation phase of the study was not appropriately designed to achieve the second objective of the study. It was not clear how and when and who implemented the interventions mentioned thereby preventing any inference. Data saturation was reached on some groups only, but the author described limitations, future research and the implication.
Johnston et al 29	Yes	Yes	Yes	Yes	Yes	No	Yes	No	Yes	The study had a small sample and no data saturation was mentioned. Reflexivity and other issues related to data analyses were not adequately reported. However, it discussed the results in perspective of the limitations, available research and future research implications and the limitations.
Erkoboni et al 22	Yes	Yes	Yes	Yes	No	No	Yes	Yes	No	The research had a problem of data saturation and positionality of researcher was not described. Results did not have quotes. The study, however, noted the wider literature and the generalisability in the local context in comparison to the original study done in the USA and study limitations.
Brown et al 30	Yes	Yes	Yes	Yes	Unclear	Unclear	Yes	No	Yes	The author identified the future implication on research and the contribution made by the study. However, the data were not analysed rigorously and there was no information on data saturation. Not enough details on reflexivity either.
Chen et al 33	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	The author identified the future implication on research and the contribution made by the study including the transferability of the findings in other settings. Limitations were discussed.
Nelson et al 31	Yes	Yes	Yes	Unclear	Yes	Unclear	Yes	No	Yes	The researcher did not clearly state why only pregnant women were targeted for the study. Data saturation, small sample size and the lack of information on researcher’s role and reflexivity were limitations. However, the data did discuss local implications considering the larger literature, as well as strengths and limitations of the study.
Liu et al 35	Yes	Yes	Yes	Unclear	Yes	No	Yes	Yes	Yes	The study was well conducted, and the researcher discussed the contribution it made in the larger context and the issue of generalisability, reliability and validity and the need for future research. However, there was inadequate reporting of actual recruitment strategy and reflexivity.
Fleisher et al 23	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	The study was well conducted, and the researcher discussed the contribution it made in the larger context and the issue of generalisability, reliability and validity.
Hunter et al 36	Yes	Yes	Yes	Yes	Yes	Unclear	Yes	No	Yes	The study was well conducted, and the researcher discussed the contribution it made in the larger context and the issue of generalisability, reliability and validity. However, reflexivity was not reported and data saturation was not reached. There was also some discordance between the total number of participants and the individual participants in each FGD.
McKenzie et al 37	Yes	Yes	Yes	Yes	No	Unclear	Yes	No	Yes	The overall design involved designing an intervention and obtaining pilot feedback. The design was reasonable but not much can be said about the reliability and validity of the research or the generalisability of it due to poor reporting of methodology and results. Data saturation and reflexivity was not mentioned.
Hall et al 32	Yes	Yes	Yes	Yes	Yes	Unclear	Yes	Yes	Yes	The study was well conducted, and the researcher discussed the contribution it made in the larger context and the issue of generalisability, reliability and validity.

CASP, Critical Appraisal Skills Programme; FGD, focus group discussion.