Magic, Mystery, Myth, or Meaningful: The 5-year Rule for Publications: Editor’s Message

Many readers and reviewers of medical journals, ­standards, and guidelines believe that information's credibility is directly influenced by the number of references within the past 5 years. Is there magic in the research and information accumulated since 2019? I believe we know the answer to this question. I am mainly considering the worldwide lull in research and publication during the pandemic. Why is there a "rule" about citing information published in the previous 5 years?When considering research to be published in medical journals, such as JAVA, the literature search that preceded the development of the research question, purpose, and aim should show a synthesis of currently available knowledge. The researcher should not simply assess the last 5 years of information and assume they have the whole story, but likewise, they shouldn't ignore new evidence.The mysterious part of the 5-year rule is that the more narrow, specialized, obscure, or novel the topic, the less likely there will be a pile of recent evidence. Sometimes, the indication of the need to research a topic is found in the gap, and sometimes, the highest level of evidence on a topic is greater than 5 years old. Should an author ignore an 8-year-old randomized control trial for a 2-year-old case study? If the only evidence in the past 5 years is low-level evidence, it would be wise to include older research.As an editor, am I describing the 5-year rule as a myth that should be ignored? Absolutely not! When reading articles, standards, or guidelines, one must understand many aspects of research, writing, and publication before simply running one's finger down the reference list and counting "out-of-date" references. If the 5-year rule were applied, textbooks would be out of date before they hit the shelf. Standards and guidelines would have a shelf-life of 1 to 2 years and published research articles of about 3 to 4 years.How can a newly published work be out of date? When one cites standards and guidelines, the year they were published is what "counts," but if one looks at the specific standard, the information used to build that standard will be at least 2 to 3 years older than the publication date. Why? Standards and guidelines begin with a systematic review of current evidence through specific protocols about search strategies, inclusion, exclusion, levels of evidence, etc. Those protocols take time, and all that work is done before developing the written standard or guideline.The publication process also ages the evidence as the manuscript moves through review, revision, and publication. Depending on the journal, this process can take 6 to 18 months and is much longer for textbooks. Knowing these problems, how is the 5-year rule meaningful in medical publications?The 5-year rule indicates that the authors have searched through recent available evidence and incorporated it into their work. When creating a research study, the first step is to assess what is already known. The search strategy may begin with a wide net and return thousands of results. Limiting the search to the last 5 years will likely bring that number down. Reviewing the reference list in current articles may lead the author to older information in textbooks and primary or foundational studies that will further inform the research.In summary, the 5-year rule is a guide, not a law. The rule's first goal is to promote the assessment of recent publications for current evidence. Older evidence may give a critical perspective; high-level evidence rarely expires in 5 years. When critiquing reference dates in any publication, the reader should consider the following:The process and time invested in the actual research.The journal's time from submission to publication.Narrowness of the topic.Level of evidence.The 5-year rule matters, but the informed reader should look at the bigger picture before dismissing the article solely on the year of article publication. I did search for references about the 5-year rule, but most were over 5 years old.