Let's be honest, review articles are popular because they are easier than studies. Studies can take months or years and require methodology, money and expertise. A review just means finding other papers and figuring out what the consensus is.

Want to prove acupuncture works and that organic food is superior? Do a review. And if you really want to promote an ideology, do an unweighted random-effects meta-analysis and make sure to include some outlier results.

Many reviews, outside cultural wars, are quite valuable. In medicine as in science, they can summarize research on a given topic and perhaps set the stage for further studies. Medical reviews can be broken into 5 main types, outlines a new paper. No one is better than the other, though they often set out to achieve different goals.

The five, writes William McGaghie, PhD, of Loyola University Chicago Stritch School of Medicine in  Academic Medicine, are narrative review, systematic review, scoping, critical-realist and open peer commentary.

A review article is, at its best, designed to accomplish integrative scholarship. The late educator Ernest Boyer, PhD, wrote that integrative scholarship puts isolated facts in perspective, makes connections across disciplines and illuminates data in a revealing way. Integrative scholarship, Boyer wrote, is "serious, disciplined work that seeks to interpret, draw together and bring new insight to bear on original research."

Research integration involves 7 steps:

Formulate the problem
Search the literature
Gather information from studies
Evaluate the quality of studies
Analyze and integrate the outcomes of studies
Interpret the evidence
Present the results.

McGaghie identifies the five traditions of writing review articles:

Narrative review. Until recently, this was the most common, influential and widely endorsed approach. An author or authors stakes out an area of published writing and aggregates the evidence based on expert opinion or judgment. Data are abstracted from the reviewed articles and compiled into evidence tables. An "expert" summarizes his or her understanding of the issues in a review article.

Systematic review. This is a distinct, reproducible research method requiring a testable hypothesis or focused research question. The literature search is systematic and comprehensive; articles are selected for inclusion according to criteria set in advance. As in narrative reviews, data are compiled into evidence tables. Data then are interpreted in the context of all relevant studies.

Scoping. This is a relatively new strategy. The intent is to produce a quick, narrative, descriptive account of the scope of current literature addressing a key research question.

Critical-realist. This is a hybrid of the narrative, systematic and scoping review methods. It relies simultaneously on both professional judgment and rigorous methodology.

Open peer commentary. In this approach, a journal solicits or commissions an article that is provocative, controversial or at the leading edge of science or scholarship. The peer-reviewed article is followed by commentaries that may endorse, refute, amplify or refine its methods, substance or conclusions. The author of the target article has the final say in the form of rebuttal, summary remarks and comments.

McGaghie writes, "Reviewers and editors should recognize and respect the five integrative scholarship traditions and also be ready to embrace new approaches to research synthesis such as network analysis now on the horizon."

Article: "Varieties of integrative scholarship: Why rules of evidence, criteria and standards matter", Academic Medicine.