Recreational cannabis legalization and alcohol purchasing: a difference-in-differences analysis.
Recreational cannabis legalization and alcohol purchasing: a difference-in-differences analysis.
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DOI：
10.1186/s42238-021-00085-x
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发表时间：
2021-07-07
影响因子：
3.7
通讯作者：
Erickson D
中科院分区：
文献类型：
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作者：
Calvert CM;Erickson D
随着大麻政策的演变，特别是考虑到酒精使用对健康和社会的不利影响，娱乐性大麻合法化是否与酒精消费的变化有关（表明存在潜在的替代或补充关系）是一个关键问题。关于这个问题的研究相对较少。本研究使用中断时间序列设计检验了娱乐性大麻合法化与美国酒精购买之间的关系。我们使用尼尔森消费者小组（2004-2017）的数据，来自美国50个州的69,761个家庭，计算了四种饮料类别（啤酒、葡萄酒、烈酒和所有酒精产品）每月购买的纯乙醇毫升数。我们使用差中差模型和稳健的聚类标准误差来比较购买的纯乙醇毫升数的变化。我们为每种饮料类别拟合模型，将三个“政策”州（科罗拉多州、俄勒冈州和华盛顿州）与未将娱乐性大麻合法化的州进行比较。在一组模型中，选择了与策略状态中的策略前购买趋势相匹配的单个控制状态。在另一组中，将政策州与所有未将娱乐性大麻合法化的州进行比较。与所有其他未将休闲大麻合法化的州相比，科罗拉多州家庭显示所有酒精产品的平均每月购买量减少了13%（估计，0.87；置信区间，0.77,0.98），葡萄酒减少了6%（置信区间，0.94,0.89,0.99）。华盛顿的估计表明，无限制样本（1.24；CI, 1.12, 1.37）和限制样本（1.18；CI, 1.02, 1.36）的烈酒购买量都有所增加。俄勒冈州每月购买的烈性酒数量明显低于其选定的比较州（0.87；置信区间，0.77,0.99），也低于其他所有未将娱乐性大麻合法化的州（0.85；置信区间，0.77,0.95）。研究结果表明，酒精和大麻之间既不是明显的替代品，也不是互补关系。随着时间的推移和获得更多的合法化后数据，未来的研究应检查更多的状态，使用大麻购买数据，并考虑在准实验研究中选择其他方法进行对照。
Whether recreational cannabis legalization is associated with changes in alcohol consumption (suggesting a potential substitution or complementary relationship) is a key question as cannabis policy evolves, particularly given the adverse health and social effects of alcohol use. Relatively little research has explored this question. This study examined the association between recreational cannabis legalization and alcohol purchasing in the USA using an interrupted time series design. We used data from the Nielsen Consumer Panel (2004–2017) from 69,761 households in all 50 states to calculate monthly milliliters of pure ethanol purchased for four beverage categories (beer, wine, spirits, and all alcohol products). We used difference-in-differences models and robust cluster standard errors to compare changes in milliliters of pure ethanol purchased. We fit models for each beverage category, comparing three “policy” states that have legalized recreational cannabis (Colorado, Oregon, and Washington) to states that had not legalized recreational cannabis. In one set of models, a single control state was selected that matched pre-policy purchasing trends in the policy states. In another set, policy states were compared to all states that had not legalized recreational cannabis. Compared to all other states that did not legalize recreational cannabis, Colorado households showed a 13% average monthly decrease in purchases of all alcoholic products combined (estimate, 0.87; CI, 0.77, 0.98) and a 6% decrease in wine (0.94; CI, 0.89, 0.99). Estimates in Washington were suggestive of an increase in spirits purchased in both the unrestricted (1.24; CI, 1.12, 1.37) and restricted sample (1.18; CI, 1.02, 1.36). Oregon showed a significant decrease in monthly spirits purchased when compared to its selected comparator state (0.87; CI, 0.77, 0.99) and to all other states without legalized recreational cannabis (0.85; CI, 0.77, 0.95). Results suggest that alcohol and cannabis are not clearly substitutes nor complements to one-another. Future studies should examine additional states as more time passes and more post-legalization data becomes available, use cannabis purchase data and consider additional methods for control selection in quasi-experimental studies.