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by markeroon 174 days ago
If we're doing anecdotes I'm sure there are lots of drunk drivers with spotless records.

I understand that you're taking issue with the idea of always being impaired, but the article indicates that there's a pretty clear association between having ingested THC and being in a car crash.
2 comments
cortesoft 174 days ago
Don't we need baseline levels to see the association?
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Panzer04 174 days ago
You think 40% of the population is using? That seems like a pretty big reach to me.
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cortesoft 174 days ago
I have no idea, but we should know the baseline if we want to know the effect
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solumunus 174 days ago
There’s also an association with having drank water and been in a car crash. This on its own can’t reasonably inform any opinions, more context is required.
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Aurornis 174 days ago
> There’s also an association with having drank water and been in a car crash

This is blatantly intellectually dishonest. If 100% of people drink water then it’s not surprising when 100% of people in car crashes have been drinking water.

If less than 40% of the population has impairment levels of THC at any given time but 40% of deceased car crash drivers have impairment levels of THC in their blood, you can’t pretend that THC use is equivalent to drinking water.

The mental gymnastics being done in this thread to try to ignore this study are fascinating.

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ModernMech 174 days ago
> If less than 40% of the population has impairment levels of THC at any given time but 40% of deceased car crash drivers have impairment levels

You're looking at two different populations in this and your other comments, drawing a false equivalence. The study is over a 6 year period, over which 103 people (40%) tested positive for THC. You're saying that because the number of people who self-reported consuming THC in the last year is 20%, that means the result of the study is eye popping and shocking because the number is 40%. But you cannot directly infer elevated risk just because a subgroup has a higher prevalence than the general population without controlling for exposure and confounders. Especially considering what we are talking about is people self-reporting they are criminals.

Moreover, fatal crashes are not randomly distributed across age groups or vehicle types, and younger people, because they are not as experienced, they drive more often, in smaller cars with fewer safety features, are more likely both to smoke THC, and die in crashes even while sober. So there's a strong sampling bias here you're not accounting for.

And this isn't downplaying the results, it's pointing out its limitations of the study and warning you not to read into it what isn't there. You seem to be shocked by the results which should cause you to dig deeper into the study. I would say the most surprising thing here is they found nothing changed before and after legalization.

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solumunus 173 days ago
> If less than 40% of the population has impairment levels of THC at any given time but 40% of deceased car crash drivers have impairment levels of THC in their blood

Yes, IF. That was my point.

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markeroon 174 days ago
Enough with the pedantry please:

"Driving under the influence of cannabis was associated with a significantly increased risk of motor vehicle collisions compared with unimpaired driving (odds ratio 1.92 (95% confidence interval 1.35 to 2.73); P=0.0003); we noted heterogeneity among the individual study effects (I2=81)".

From https://www.bmj.com/content/344/bmj.e536

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