The control group rated higher in all areas. 參照組在所有的領域的等級都比較高。
Grouping longer-term abstainers and recent quitters together as the reference group inflated the observed protective effect of alcohol, the authors note. 作者稱,將長期禁酒組和最近戒酒組合併作為一個參照組后,所觀察到的飲酒預防作用更大。