Tyrer Stephen, Heyman Bob
Newcastle University, UK.
University of Huddersfield, UK.
BJPsych Bull. 2016 Apr;40(2):57-60. doi: 10.1192/pb.bp.114.050203.
Surveys of people's opinions are fraught with difficulties. It is easier to obtain information from those who respond to text messages or to emails than to attempt to obtain a representative sample. Samples of the population that are selected non-randomly in this way are termed convenience samples as they are easy to recruit. This introduces a sampling bias. Such non-probability samples have merit in many situations, but an epidemiological enquiry is of little value unless a random sample is obtained. If a sufficient number of those selected actually complete a survey, the results are likely to be representative of the population. This editorial describes probability and non-probability sampling methods and illustrates the difficulties and suggested solutions in performing accurate epidemiological research.
对人们的意见进行调查充满困难。从回复短信或电子邮件的人那里获取信息,要比试图获得一个具有代表性的样本更容易。以这种方式非随机选择的人群样本被称为便利样本,因为它们易于招募。这就引入了抽样偏差。这种非概率样本在许多情况下都有其优点,但除非获得随机样本,否则流行病学调查几乎没有价值。如果足够数量的被选中者实际完成了调查,结果可能会代表总体。这篇社论描述了概率抽样和非概率抽样方法,并说明了在进行准确的流行病学研究时所面临的困难及建议的解决方案。