*Commentary*

Aspects of the study that might threaten or enhance its validity. This could include fidelity to treatment, quality of counterfactual, extraneous/confounding variables, other programmes going on that may have a ffected the results, and conflicts of interest.

## **Appendix B**



## **Appendix C**

The table summarises pieces that were reviewed and rated below 2. These tended to be small-scale, have considerable attrition, no clear comparator, and/or rely on reports of intention to stay or leave.











