Evidence-Based Practice: How to Evaluate What You Read

Systematic reviews and meta-analysis are affected by the studies that are included or excluded. A number of biases are common, including excluding unpublished data, non-English language publications, and non-indexed articles. In addition, there can be a differential impact based on the quality and comparability of studies. In this article, we review the potential significance of these biases. Psychopharmacology Bulletin. 2003;37(4):88-91.