Nothing so practical as theory: a rapid review of the use of behaviour change theory in family planning interventions involving men and boys.

Our findings highlight the range of prevailing theories of change used for family planning interventions involving men and boys, and the considerable variability in their reporting. Programmers and policy makers would be best served by unified reporting and testing of intervention theories of change. There remains a need for consistent reporting of these to better understand how complex interventions that seek to involve men and boys in family planning may lead to behaviour change.