9.1.2 - Not just effectiveness - JBI umbrella reviews

Similar to Cochrane, the JBI has historically focused on reviews that inform the effectiveness of an intervention or therapy; however the emphasis on “best available” evidence in JBI reviews of effectiveness has not been confined solely to randomized controlled trials and other experimental studies that occupy the uppermost levels of the evidence hierarchy.

JBI Umbrella Reviews are intended to compile evidence from multiple research syntheses. Any review author will recognize the advantage of having a good understanding of study design and research methodologies, whether quantitative or qualitative in nature. Similarly, it is recommended that reviewers intending or attempting to undertake a JBI Umbrella Review should have a good understanding of systematic reviews and the diversity and methodological nuances among the various types of reviews (and different organizations and authors that conduct them) before conducting an Umbrella Review themselves.

The reasons for conducting a JBI Umbrella Review are manifold. The principal reason is to summarize evidence from many research syntheses (Becker and Oxman 2011). These may include analyses of evidence of different interventions for the same problem or condition, or evidence from more than one research synthesis investigating the same intervention and condition but addressing and reporting on different outcomes. Similarly, a researcher or reviewer may wish to summarize more than one research synthesis for different conditions, problems or populations.3 The principle focus of a JBI Umbrella Review is to provide a summary of existing research syntheses related to a given topic or question and not to re-synthesize, for example, the results of existing reviews or syntheses with meta-analysis or meta-synthesis.

A reviewer familiar with the JBI methodology for the conduct of systematic review will appreciate that many questions that are asked in health care practice do not lend themselves directly to experimentation or gathering of numerical data to establish the answer regarding what the effectiveness or outcomes of a particular intervention. Rather, the questions are more of how and why interventions do or do not work, and how recipients of the intervention may experience them.

As a result, many JBI syntheses are of original qualitative research and apply a meta-aggregative approach to synthesis of qualitative data (see Chapter 2). Similarly, JBI Umbrella Reviews may find they inevitably ask questions that direct the reviewer predominantly to existing qualitative reviews. As with the combinations of PICO elements to organize the conduct an Umbrella Review mentioned above, the common denominator or feature across such multiple qualitative syntheses may be the population or subpopulation of interest, coupled with the context of the review question.