General Descriptors for the Overall Quality Rating
| Design | Sample Size | Statistics | |
|---|---|---|---|
| Good | Case control, meta-analysis, pre-post | >500 | LCA, ROC, regression, power/effect analyses |
| Fair | Retrospective case series | 100–500 | Regression, correlation |
| Poor | Retrospective case series | <100 | Descriptive or none, low or absent power |
Note. Descriptors are the factors common to the completed NIH tools used for this analysis: e.g., “Good” studies used advanced statistics and case-control, meta-analytic, or pre-post designs.
Abbreviations: LCA = latent class analysis, ROC = receiver operating characteristic.