The control group rated higher in all areas. 参照组在所有的领域的等级都比较高。
Grouping longer-term abstainers and recent quitters together as the reference group inflated the observed protective effect of alcohol, the authors note. 作者称,将长期禁酒组和最近戒酒组合并作为一个参照组后,所观察到的饮酒预防作用更大。