What’s the point of asking? A review of the reliability of self-reported measures of sexual behaviour

This event is co-organised with City, University of London and the European Social Survey
  • Event time:
    10th April 2024 13:00 – 14:00
  • Format:

In this survey methods webinar, independent researcher Ignacio Franco Vega will review the reliability of self-reported measures of sexual behaviour. The presentation will cover reliability in general, how it is measured, the subtleties involved in using biological markers and the consequences that unreliable results might have in research and policy. Self-reported measures are the primary source of information to study sexual behaviour.

However, they present various issues that can potentially bias the results of our research (e.g., social desirability, recall errors, inadequate question and answer structures). This study aims to establish the size of such bias.

Ignacio Franco Vega conducted a rapid review to identify studies that assessed the reliability of self-reported measures. This focused on studies that contrast self-reported condom use with biological markers of semen exposure. The investigation reviewed 33 studies with contrasting self-reported measures and biomarkers (Prostate-specific antigen and Y-chromosome DNA). Studies were conducted worldwide, but most focused on at-risk groups in sub-Saharan Africa. All studies showed substantial inconsistencies between the two sources. Discrepancies range between 9% to 70% of participants.

However, there are concerns about the validity of the PSA and YcDNA as a biomarker of semen exposure. Several confounding factors might create both false positives and negatives, including the estimated rate of biomarker decay, endogenous presence of PSA in women and non-standardised thresholds for a positive result.

The study found that self-reported measures of condom use are unreliable; scientists and policymakers should be cautious when concluding anything from them. Biomarkers, albeit useful, are far from being a perfect measure.



  • Ignacio Franco Vega
    Social researcher
    Ignacio Franco Vega is a mixed-methods social researcher interested in evidence-based interventions and methodological innovation. He did an MSc in Social Research Methods at LSE and has a PhD in Social and Policy Sciences from the University of Bath; his thesis used a multi-method approach to identify the best way to promote condom use in love hotels in Lima, Perú. He has been working for thirteen years as an independent consultant, helping to design or assess policies on topics ranging from education and health to equality and inclusion. He has been responsible for the research design, data collection, and analysis of multiple projects involving the WHO, British Council, Advance HE, and the Office for Students.