Youth development programmes aimed at reducing pregnancy rates and health risk behaviour in teenagers have received strong support in many countries. Proponents of such programmes claim that they are holistic and can focus on the supports, opportunities, and services needed for success; they can tackle multiple risk behaviours, which are thought to be inter-related; and they can help build protective factors as well as reduce risk factors.

One of the most effective youth development programmes, the Children’s Aid Society (CAS) Carrera programme, reduced pregnancy by about a half over three years. Its results have been widely reported,1 and this has led to the implementation of formally sanctioned CAS Carrera programmes, unsanctioned CAS Carrera-type programmes, and other types of youth development programmes.

In the linked matched comparison study (doi:10.1136/bmj.b2534), Wiggins and colleagues evaluated a programme based on the CAS Carrera programme and other youth development programmes.2 This programme did not reduce the occurrence of pregnancy, however. Instead, pregnancy was significantly more common in the intervention group than in the matched comparison group (16% v 6%; adjusted odds ratio 3.55, 95% confidence interval 1.32 to 9.50). These results suggest that at best the programme had no effect, and at worst it had a negative …