How it works: Scientists assign participants particular commercial marijuana products with already-known chemical makeup and potency, which the subjects go out and purchase for themselves. The researchers go to the participants’ homes and first perform tests while they are sober. They then measure the effects of the drug after it is smoked, eaten, vaped, etc. But the researchers never see the commercial product itself.
Precision: While the studies are not as precise as a normal lab study, they are as good as it gets given the legal restrictions on researchers.