Editors—When the phrase “the best available research evidence” is used in the evidence-based practice literature, just what is meant? One answer is that the best research evidence consists of all available and relevant findings that were produced by scientifically sound studies. Although meta-analyses and integrative research reviews, which analyse collective evidence from all or at least many studies, are being published with increased frequency, there continues to be considerable focus on the appraisal and use of the findings of single studies.

Knowledge for practice formats based on single studies often have limitations including: (a) the full scope of evidence on the subject is not considered, (b) the findings presented are isolated from the findings of other studies on the issue, and (c) the findings are of limited value to practitioners. To illustrate these points, consider the abstract and commentary pertaining to the study on the relation between unintended pregnancy and intention to breast feed by …