Percent-of-Maximum Cannabis Ratings Did Not Compare Absolute Severity
The paper’s average percent-of-maximum curve normalized each participant to that person’s own highest self-rating. Equal percentages on that graph did not necessarily mean equal absolute symptom severity across participants.
The denominator was personal
Wurz and DeGregorio summarized self-assessments from seventy-four participants after cannabis smoking. Each person’s ratings were expressed relative to that individual’s maximum reported level, then combined over time. This emphasizes the shape of recovery relative to each person’s peak rather than preserving all between-person differences in raw ratings.
A percentage does not become a common functional scale
A participant whose highest rating was modest and another with a stronger highest rating can both reach 100% of their own maximum. An average later value near 10% of maximum is therefore not a direct measurement of ten-percent driving impairment. Nor does it establish that every participant had recovered by that time.
Retain the outcome definition
The underlying assessment was subjective rather than an on-road driving endpoint. Variable exposure, participant characteristics and the limited observation period constrain application. The paper also reanalyzed data connected to an earlier breath-testing report, so these are not wholly independent cohorts. Its normalized curve can describe a group pattern without supplying a universal safe-driving deadline or an individualized severity estimate.
Related analysis: baseline and post-smoking breath findings.
Research cited
Wurz and DeGregorio (2022). Indeterminacy of cannabis impairment and THC levels in blood and breath. DOI: 10.1038/s41598-022-11481-5.
