Scott updates his stance on marijuana legalization based on new data showing increased traffic accidents, but remains uncertain due to the complexity of the issue. Longer summary

Scott Alexander revisits his previous analysis of marijuana legalization, focusing on its effects on road traffic accidents. New studies show a 5-6% increase in car crashes and fatalities in states with legalized marijuana, contradicting his earlier prediction of a decrease. This shifts his assessment from slightly positive to slightly negative. However, he emphasizes the weakness of the math and the many assumptions involved. The post also considers other factors like people's enjoyment of marijuana, its comparison to alcohol and SSRIs, potential cancer risks, and tax implications. Scott concludes without a firm position, acknowledging the complexity of the issue. Shorter summary

Scott Alexander examines evidence on marijuana legalization's effects on usage, health, and drug war costs, finding uncertainties too large for firm conclusions but suggesting traffic accidents may be the key factor. Longer summary

Scott Alexander examines the evidence around marijuana legalization, looking at its effects on usage rates, health impacts, and costs of the drug war. He finds that decriminalization and medical marijuana don't seem to increase youth usage much, but full legalization might increase adult use by 25-50%. Health effects are unclear but may include IQ declines and slightly increased psychosis risk. The costs of the drug war are significant in terms of arrests and spending, but relatively few people are in prison solely for marijuana. Scott attempts a utilitarian analysis comparing costs and benefits of legalization, but finds the uncertainties too large to draw firm conclusions. He suggests the most important factor may be how legalization affects traffic accidents. Shorter summary