Students without prior research experience may not know how to conceptualize and design a study. This article explains how an understanding of the classification and operationalization of variables is the key to the process. Variables describe aspects of the sample that is under study; they are so called because they vary in value from subject to subject in the sample. Variables may be independent or dependent. Independent variables influence the value of other variables; dependent variables are influenced in value by other variables. A hypothesis states an expected relationship between variables. A significant relationship between an independent and dependent variable does not prove cause and effect; the relationship may partly or wholly be explained by one or more confounding variables. Variables need to be operationalized; that is, defined in a way that permits their accurate measurement. These and other concepts are explained with the help of clinically relevant examples.

没有先前研究经验的学生可能不知道如何概念化和设计研究。本文解释了如何理解变量的分类和操作是该过程的关键。变量描述了正在研究的样本的各个方面；之所以这样称呼它们，是因为它们的价值因样本中的主题而异。变量可以是独立的或相关的。自变量影响其他变量的值；因变量的值受其他变量的影响。假设陈述了变量之间的预期关系。自变量和因变量之间的显着关系不能证明因果关系；这种关系可以部分或全部由一个或多个混杂变量解释。变量需要操作化；那是，以允许其准确测量的方式定义。在临床相关示例的帮助下解释了这些和其他概念。