Something that is perhaps of value in examining the value of such sites is a meta analyses of existing studies.
The most interesting quote in the story is the following:
But this might be the most rigorous analysis yet conducted. “If you impose even a modest methodological bar, and then (supportive studies’) effects go away, to me that’s worrisome,” Stanford health policy professor Keith Humphreys told Vox.He was commenting on the fact the majority of studies supporting the sites were tossed out by the authors of the meta analyses. If the suggestion is most of the supportive studies were scientifically invalid then where does that leave us?
https://nationalpost.com/opinion/chris-selley-studys-inconvenient-evidence-on-safe-injection-sites-could-be-bad-news-for-proponents