Table 3 Description of variables used in the quality assessment
Variable name | Description |
|---|---|
Conflict of interest | Were any of the authors affiliated with the project described in the study in any way that could result in a conflict of interest (e.g. currently or previously employed by the project, served as an advisor on the project, or funded by the same source)? Coded as 1 (yes or unsure), 0 (no) |
Methods description | How well were the methods in the paper reported. Coded as 1 (not very clear (missing information) or not reported) and 0 (very clear) |
Study design category | How could the design of the study be characterized? Coded as 4 (case series or cross sectional study), 3 (case control study, cohort study, or historically controlled study), 2 (interrupted time series study), 1 (controlled before-and-after study or non-randomized control trial) and 0 (randomized control trial). Note only categories 3 and 4 were present in our sample |
Controls | Were appropriate control cases included in the study? Coded as 1 (no or partial), and 0 (yes) |
Confounds | Did the study account for and minimize effects associated with potential confounding variables? Coded as 1 (no or partial), 0 (yes) |
Analysis type | What type of analysis did the author use? Coded as 2 (qualitative analysis or quantitative analysis with descriptive or observational statistics), 1 (analysis of variance, t-test, statistical correlation or other bivariate analyses), 0 (multivariate regression or other multivariate analyses). |