Two dimensional hierarchy of study utility
| Study design | Study population |
|---|---|
| *The effectiveness of interventions given in a clinical setting was outside the scope of the review. | |
| Randomised controlled trial | Households or local residents |
| Controlled panel study (repeated measures on the same participants) | Subset of local population (drivers, commuters, or school pupils) |
| Controlled repeated cross sectional study Controlled retrospective study Uncontrolled panel study (repeated measures on the same participants) Uncontrolled repeated cross sectional study | Participants in a targeted intervention already selected from one of the groups above Passers by at, or visitors to, a study location Patients* Vehicles |
| Uncontrolled retrospective study | Population not clear |
| Case study of trends in mode share | |
| Design not clear | |