The RIPPLE (randomised intervention of pupil peer led sex education) study is a cluster RCT designed to investigate whether peer delivered sex education is more effective than teacher delivered sessions at decreasing risky sexual behaviour. It involves 27 English secondary schools and follow-up to age 19. In the schools randomised to the experimental arm, pupils aged 16-17 years (given a brief training by an external team) delivered the programme to two successive year cohorts of 13-14 year olds. Control schools continued with their usual teacher led sessions. The trial was informed by a systematic review and pilot study in four schools.7,8
Its design by a multidisciplinary research team includes an integral process evaluation that has four aims: to document the implementation of the peer led intervention and sex education in control schools; to describe and compare processes in the two forms of sex education; to collect information from study participants (schools and students) about the experience of taking part in the trial; and to collect data on individual school contexts.9
Box 1: Methods for data collection in the RIPPLE trial process evaluation
- Questionnaire surveys of students and peer educators
- Focus groups with students and peer educators
- Interviews with teachers
- Researcher observation of peer led and teacher led sex education
Several methods were used to collect process data (box 1), including questionnaire surveys, focus groups, interviews, researcher observations, and structured field notes. Some methods, such as questionnaire surveys, were also used to collect outcome data. Other methods, such as focus groups and interviews with school staff and peer educators, were specific to process evaluation.
The outcome results by age 16 showed that the peer led approach improved some knowledge outcomes; increased satisfaction with sex education; and reduced intercourse and increased confidence about the use of condoms in girls. Girls in the peer led arm reported lower confidence about refusing unwanted sexual activity (borderline significance). The incidence of intercourse before age 16 in boys and of unprotected first sex, regretted first intercourse (or other quality measure of sexual experiences or relationships), confidence about discussing sex or contraception, and some knowledge outcomes for both girls and boys were not affected.10
We analysed process data in two stages. Before analysing outcome data (box 2), we analysed the data to answer questions arising from the aims outlined above. The hypotheses generated were tested in statistical analyses that integrated process and outcome data to address three questions:
- What was the relation between trial outcomes and variation in the extent and quality of the implementation of the intervention?
- What processes might mediate the observed relation between intervention and outcomes?
- Did subgroups of students and schools differ in their responses to the intervention?
We used several strategies to combine the different types of data. These included on-treatment analyses, in which results for students who received the peer led intervention were compared with results from the standard intention to treat approach (where allocation to, rather than receipt of, the intervention forms the basis of the analysis). We then carried out regression analyses and, where appropriate, tests for interactions, to examine the relation between key dimensions of sex education, subgroups of schools and students most and least likely to benefit from the peer led programme, and study outcomes (further details are available elsewhere).11,12
We used regression analyses because they are best for dealing with many types of outcome, assessing the impact of mediating factors, and analysing subgroups.13,14
These strategies provided answers to our three questions.
- More consistent implementation of the peer led programme might have had a greater impact on several knowledge outcomes and reduced the proportion of boys having sex by age 16, but it would not have changed other behavioural outcomes.
- There were key interactions between the extent to which sex education is participative and skills based and who provided it: when sex education was participative and skills based, the peer led intervention was more effective, but when these methods were not used, teacher led education was more effective.
- Peer led sex education was less good at engaging students most at risk of poor sexual health (risk was assessed using housing tenure, attitude to school, and educational aspirations); the peer led approach was better at increasing knowledge in schools serving “medium” rather than “low” risk populations (assessed using the proportion of students receiving free school meals).