批判性阅读研究：对内部效度的威胁。

J Post Anesth Nurs. 1994 Oct;9(5):303-7.

Internal validity refers to the extent to which it is possible to attribute the change in the dependent or outcome variable in a study to manipulation in the independent variable. This article will discuss the frequent threats to internal validity and how to recognize them.

内部效度指的是在一项研究中，能够将因变量或结果变量的变化归因于自变量操纵的程度。本文将讨论内部效度常见的威胁因素以及如何识别这些因素。