Quantitative Surveys in Hard-to-Reach Populations: The Experience of the ‘Observatoire Français Des Drogues Et Des Toxicomanies’

Abstract

This article presents a research device (drawn up by the ‘Observatoire francais des drogues et des toxicomanies’ or OFDT) for exploring drug consumption practices among ‘hard-to-reach users’. The OFDT’s aim is to put forward a coherent and precise understanding of phenomena relating to drug use and to monitor developments from a national perspective, despite regional differences. The scope of observation focusses on the primary areas of drug use in France. The analysis over time of quantitative and qualitative data also made it possible to divide up the theoretical and heterogeneous unit formed by drug users (DUs) in terms of population types and sub-populations. They have different characteristics and engage in different practices, which do not always develop in the same way. Sometimes they are geographically unstable. The OFDT’s experience of probability studies on DUs or populations with a high prevalence of drug use is applied in a ‘capture-recapture’ study that aims at estimating the prevalence of problematic drug use in six French cities and a quantitative survey based on a sampling plan with an ethnographically based approach in party environments with a focus on electronic music. These complex sampling studies prove indispensable, in particular in measuring the prevalence of drug use in populations not exclusively made up of drug users. However, we believe that, on their own, they cannot measure a phenomenon or monitor its developments since there are several sources of bias associated with sampling and the collection of data in surveys on hard-to-reach populations. We believe that comparing their results not only with the quantitative data from other sources, in particular the time series collected from users of centres for DUs but also with ethnographic data is indispensable in order to monitor these trends.