Methodological Considerations for Assessing the Impact of Sex Work Decriminalisation on HIV Testing Frequency Among Female Sex Workers in Katutura, Namibia

Female sex workers in sub-Saharan Africa bear a disproportionate burden of HIV. Structural interventions, such as the decriminalisation of sex work, are hypothesised to improve HIV outcomes. Robust methodologies to measure the specific impact of decriminalisation on behaviours like HIV testing frequency are underdeveloped in localised settings such as Katutura, Namibia. This article outlines a methodological framework for assessing the impact of sex work decriminalisation on HIV testing frequency among female sex workers in Katutura, Windhoek. The objective is to detail a study design that isolates the effect of legal change while accounting for local socio-structural factors. The proposed design is a mixed-methods, quasi-experimental study. A retrospective cohort of female sex workers will be established using respondent-driven sampling. Quantitative data on HIV testing frequency will be collected via structured surveys and analysed using interrupted time-series analysis, comparing periods before and after decriminalisation. Qualitative data from in-depth interviews will explore contextual mechanisms. Key considerations include defining operational measures of 'decriminalisation', constructing a valid comparison timeline, and addressing ethical concerns around participant safety. As a methodology article, this paper presents no empirical results. The proposed analytical framework anticipates that decriminalisation will be associated with a measurable increase in reported HIV testing frequency. Evaluating the health impacts of sex work decriminalisation requires methodologically rigorous approaches tailored to the local environment. This framework provides a model for isolating the effect of legal change on HIV testing behaviours. Future research should adopt longitudinal, mixed-methods designs to capture causal pathways and contextual nuances. sex work, decriminalisation, HIV testing, methodology, female sex workers, Namibia, interrupted time series, mixed methods This article contributes a detailed methodological framework for studying the impact of a specific legal change on a key HIV-related behaviour within a defined, high-risk population and geographical context.