Jang R
Am J Hosp Pharm. 1980 Mar;37(3):398-403.
The purposes and criteria for formulating a design of research, conditions for judging causality, and use of research design as a control of variance are discussed. The purpose of a research design is to provide a plan of study that permits accurate assessment of cause and effect relationships between independent and dependent variables. The classic controlled experiment is an ideal example of good research design. Factors that jeopardize the evaluation of the effect of experimental treatment (internal validity) and the generalizations derived from it (external validity) are identified. Sources of variance can be controlled by eliminating a variable, randomization, matching, or including a variable as part of the design. A research project should be so designed that (1) it answers the questions being investigated, (2) extraneous factors are controlled, and (3) the degree of generalization that can be made is valid.
本文讨论了制定研究设计的目的和标准、判断因果关系的条件以及将研究设计用作方差控制的方法。研究设计的目的是提供一个研究计划，以便能够准确评估自变量和因变量之间的因果关系。经典的对照实验是良好研究设计的理想范例。文中识别了那些会危及对实验处理效果评估（内部效度）及其得出的概括（外部效度）的因素。方差来源可以通过消除变量、随机化、匹配或在设计中纳入变量作为一部分来加以控制。一个研究项目的设计应做到：（1）回答所研究的问题；（2）控制无关因素；（3）所做概括的程度是有效的。
