Table 2.
Checklist for sources of external bias†
| Question | Yes/no/unclear | Description |
|---|---|---|
| Population bias | ||
| Study subjects in idealized study drawn from population identical to target population, with respect to age, sex, health status etc.? | ||
| Does extent of population bias depend on magnitude of intervention effect? | ||
| Intervention bias | ||
| Active intervention in idealized study identical to target active intervention in dose, timing etc.? | ||
| Does extent of intervention bias depend on magnitude of intervention effect? | ||
| Control bias | ||
| Control intervention in idealized study identical to target control intervention? | ||
| Does extent of control bias depend on magnitude of intervention effect? | ||
| Outcome bias | ||
| Study outcome for idealized study identical to target outcome? | ||
| Does extent of outcome bias depend on magnitude of intervention effect? | ||
†The empty areas are to be completed.