“临床实效研究”或“实效研究”（Outcomes Research），也有人称之为“效果研究”，是近年来在国际临床医学领域迅速发展起来的新学科。在许多临床试验（Clinical Trials）研究中，凡是有多种疾病、有多种并发症或服用多种药物的病人常常被排除在外。临床实效研究则是研究药物或其它医疗措施在非控制的真实临床情况下（real world）的效果及经济和社会效益等。临床试验研究（如RCT）和实效研究对于充分了解一个医疗产品的实际医疗效果、效益和安全性有着同样重要的意义，只是方法学上有所不同。

Outcomes research is a branch of public health research, which studies the end results of the structure and processes of the health care system on the health and well-being of patients and populations. According to one medical outcomes and guidelines source book - 1996, Outcomes research includes health services research that focuses on identifying variations in medical procedures and associated health outcomes. Though listed as a synonym for the National Library of Medicine MeSH term "Outcome Assessment (Health Care)", outcomes research may refer to both health services research and healthcare outcomes assessment, which aims at Health technology assessment, decision making, and policy analysis through systematic evaluation of quality of care, access, and effectiveness.