Abstract
Sexual and reproductive health interventions' effectiveness should be evaluated using a valid instrument. This study aimed to validate a questionnaire on sexual and reproductive health in adolescents and young adults from São Tomé and Príncipe who voluntarily enrolled in a vocational school in Portugal to complete their 12th school year and obtain a professional card.A questionnaire consisting of perception and knowledge sections was adapted from previous questionnaires. We followed the steps of psychometric analysis. Firstly, we assessed face validity and content validity. We used factorial analysis to validate the perceptions section (which included Likert-type questions). For the knowledge section (which consisted of multiple-choice questions), we used the key check, discrimination index, and difficulty index. We evaluated internal consistency through Cronbach's alpha for the perceptions section and the Kuder-Richardson score for the knowledge section.Out of 105 invited students, a total of ninety students were enrolled in this study, of whom 88 completed most of the questions. The exploratory analysis showed that most students agreed with the right to refuse intercourse. However, while approximately 23% disagreed that consensual sex among adult women or men is always wrong, around the same proportion agreed. A considerable number of students recognized condoms and pills as effective methods of contraception. However, most students were unfamiliar with other methods. Most knowledge questions showed acceptable difficulty levels, and the discrimination index varied among questions. The knowledge questions demonstrated good consistency levels. This study enabled us to develop an appropriate instrument for evaluating the effectiveness of public health interventions and identifying specific knowledge gaps in migrant populations from low-income countries. This will help prioritise topics to be addressed in sexual health education sessions.