样本选择偏差（sample selection bias）与幸存者偏差（survivorship

Question

样本选择偏差（sample selection bias）与幸存者偏差（survivorship bias）如何区分？感觉幸存者偏差也是样本偏差的一种啊！

Answer 1

Selection bias is the selection of individuals, groups or data for analysis in such a way that proper randomization is not achieved, thereby ensuring that the sample obtained is not representative of the population intended to be analyzed.

而 servivorship bias 是即便你的sample 是通过科学的和完全random的一样会存在的情况，比如说你分析金融危机过后各种基金的回报情况时候 即便你是完全随机抽样，你还是选不到那些已经挂掉的。剩下的本来就相对优质。