Table 9.
Framework for reviewing factors influencing heterogeneity across included studies
| 1. Population | 2. Intervention | 3. Comparator | 4. Outcomes | 5. Timing and tools | 6. Study design and conduct |
|---|---|---|---|---|---|
| Heterogeneity factors for each major domain driving heterogeneity | |||||
| - Baseline risk for primary outcome (without intervention) as well as for intervention-related harms - Other main population differences hypothesized to drive differences in intervention effects |
- Differences in the approach, intensity, modalities, or components of interventions that could drive differences in intervention effects | - Components of comparison condition that might influence the size/direction of intervention effects | - Comparability of inpatient outcomes across studies that might influence intervention effects | - Appropriateness and comparability of outcome assessment timing considering hypothesized intervention effects and natural history | - Variability in design and conduct of studies within a body of evidence |
| Potential categories of variable approaches by individual studies | |||||
| - Risk based (low, average, high, unclear, mixed) - Other selected (age, race/ethnicity, sex, education, socioeconomic status) |
- Approach (generic, targeted, tailored) - Intensity/dose (hours, duration, staff) - Modalities (simple, multiple) - Components (single, co-interventions) |
- Placebo - Usual care - Active/alternative treatment - Incremental effect (intervention and comparator only, vary by one or minimal components) |
- Type of outcome (primary, secondary, incidental) - Number and type of beneficial outcomes (one main, multiple, composite) - Number and type of harmful outcomes (one main, multiple, composite) - Validity of outcome measurement |
- Appropriateness (measured or timed after intervention ended, delayed measurement at meaningful timeframes - Comparability (consistent timeframe between studies, variable timeframe for study) |
- Quality rating (good, fair, poor) - Risk of bias (lack of allocation concealment, lack of blinded outcome assessment, inappropriate randomization) |