每日一题_2023.09.03

A pharmaceutical company has created a new drug that, when taken daily, is thought to be highly effective at preventing the onset of migraines. The company would like to market the drug and is conducting a study to look at its benefits and possible risks. In coordination with a physician at a local hospital, it enrolls 800 people for the study. The physician places 100 patients with the worst and most frequent migraines in the medication group, as he thinks that they are in most need of the drug’s benefit. Which of the following best explains why the drug may not perform up to expectations?

一家制药公司发明了一种新药，如果每天服用，被认为可以非常有效地预防偏头痛的发作。该公司希望将该药物推向市场，并正在进行一项研究，以了解其益处和可能的风险。在与当地医院的一名医生的协调下，该公司招募了800人参与这项研究。医生将100名偏头痛最严重和最频繁的患者纳入药物治疗组，因为他认为他们最需要药物的益处。下列哪一项最好地解释了为什么药物的性能可能达不到预期?

(A) Differences in group size 群体规模的差异

(B) Late-look bias后视偏倚

(C) Recall bias回忆偏差

(D) Sampling bias抽样偏倚

(E) Selection bias选择偏倚

答案解析：

选择偏倚在这种情况下表现出来。医生正在为治疗组挑选病情较重的病人(即最需要获益的病人)。安慰剂组患者更健康，症状更少，更有可能获得更好的结局。因此，当需要收集数据时，与安慰剂相比，药物的有益作用可能会被削弱。

正确答案：E