The public health impact of safe consumption sites (SCS, or facilities that provide a safe, clean space for people to inject or consume pre-obtained drugs under observation of trained staff) cannot currently be assessed in the US using the gold standard randomized controlled trial given their current lack of legal support. Yet, evidence specific to SCS’s impact in the US is considered necessary to warrant their adoption. In response to the opioid-related overdose epidemic, a SCS opened in 2014 in an urban area within the US without waiting for formal sanction. With data from an observational cohort study of 500 people who inject drugs residing near the SCS, we estimate the individual level causal effect of SCS use. We demonstrate the utility of applying the covariate balancing propensity score-based weighting technique to generate causal estimates  and offer strategies for how to present compelling results when key descriptives, like those which might be telling to the location of the unsanctioned SCS, need to be concealed.
1. Imai, K. and Ratkovic, M. (2014) Covariate balancing propensity score. J. R. Stat. Soc. B;76: 243-263.