A major meta-analysis published earlier this year that questioned the empirical evidence for supervised drug consumption sites has been retracted by the International Journal of Drug Policy.
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But the meta-analysis, which I reported on shortly after it published, concluded that supervised consumption sites have a small favorable relation to drug-related crimes, but no significant effect on several other outcomes, like overdose mortality and syringe sharing. In short, the meta-analysis didn't conclude that supervised consumption sites were bad, but they didn't appear to do much on key outcomes like overdose death.
But the meta-analysis apparently had serious methodological flaws in how it evaluated outcomes. Here's the technical explanation from the International Journal of Drug Policy:
"This [retraction] is supported by the authors' acknowledgement of methodological weaknesses linked to the pooling of diverse outcomes into a single composite measure. ... Accordingly, the authors acknowledge that the combined effect size reported in the original paper should be discounted. Given that the composite measure was a key finding reported by the original paper, the decision to retract the paper from publication had been made, including with the consent of the authors."
In other words, the researchers combined a bunch of different outcome variables into one measurement, potentially obfuscating important differences between the outcomes.
