PT  - JOURNAL ARTICLE
ED  - ,
TI  - Understanding observational studies
AID  - 10.1136/dtb.2016.9.0426
DP  - 2016 Sep 01
TA  - Drug and Therapeutics Bulletin
PG  - 105--108
VI  - 54
IP  - 9
4099  - http://dtb.bmj.com/content/54/9/105.short
4100  - http://dtb.bmj.com/content/54/9/105.full
SO  - Drug Ther Bull2016 Sep 01; 54
AB  - The development of evidence-based medicine has encouraged clinicians to consider the best available evidence when making clinical decisions, individualised for the patient.1,2 A hierarchy of levels of evidence about therapy is described, with the highest being meta-analyses and large, well-designed randomised controlled trials.3-5 Lower down the hierarchy are observational studies, a group that includes cohort, case-control and cross-sectional studies. Here we describe the benefits and limitations of observational studies, and how to assess their quality.