van der Meulen Jan
Health Services Research Unit, London School of Hygiene and Tropical Medicine, London, United Kingdom.
Transplantation. 2008 Jul 15;86(1):30-1. doi: 10.1097/TP.0b013e31817d4f99.
The use of a one-dimensional "hierarchy of study designs" to grade the evidence on the effectiveness of healthcare interventions is problematic as it may underestimate the limitations of randomized controlled trials and overstate those of observational studies. Observational studies can be an alternative to randomized controlled trials or a source of complementary information. The role of observational studies will vary in different situations. Depending on their topic, design, and methods of analysis, observational studies may be as credible as randomized studies.
使用一维的“研究设计层次结构”来对医疗保健干预措施有效性的证据进行分级存在问题，因为它可能低估随机对照试验的局限性，而高估观察性研究的局限性。观察性研究可以作为随机对照试验的替代方法，或者作为补充信息的来源。观察性研究在不同情况下的作用会有所不同。根据其主题、设计和分析方法，观察性研究可能与随机研究一样可信。
