The Model’s Fifteen-Milligram THC Reference Was Not a Measured Dose for Every Participant
The population model expressed inhaled THC exposure relative to an assumed fifteen-milligram bioavailable reference. That reference was a scaling convention, not a documented administered dose shared by all participants.
The model estimated a multiplier
For modeling purposes, the investigators assumed a sixty-milligram THC joint with twenty-five percent bioavailability, yielding a fifteen-milligram reference. Each participant’s estimated inhaled dose was represented as a multiple of that value. Different fitted multipliers represented different modeled exposures.
The reference and the observation have separate roles
Blood concentrations were measured, while the reference dose and model structure helped interpret those measurements. Multiplying the fitted fraction by fifteen produces a model-derived dose estimate. It is not an additional direct measurement of cannabis mass, inhalation efficiency or absorbed THC.
A unit convention is not a universal smoking efficiency
The assumed percentage should not be assigned to every joint, vape device or person. Participants used their preferred products ad libitum, and inhalation behavior could vary substantially. The study supports examining that variability through a model; it does not eliminate it with one reference value. A forensic opinion should retain the reference convention and uncertainty when discussing modeled dose, rather than treating the nominal fifteen milligrams as the amount every participant actually absorbed.
Related analysis: the study’s broader findings and limitations.
