23 April 2021
Publication bias: the problem that won’t go away. That’s the title of a 1993 study by Kay Dickersin, then at the Department of Epidemiology and Preventive Medicine at the University of Maryland School of Medicine, and Yuan-I Min at the Department of Epidemiology at the Johns Hopkins University. In their study, published in the Annals of the New York Academy of Sciences, the two authors define publication bias as “any tendency on the parts of investigators or editors to fail to publish study results on the basis of the direction or strength of the study findings.” More than 25 years later, not only is the problem of publication bias as they defined it still with us, it has metamorphosized into new forms.
Currently, publication bias is recognized as the preference of journals for publishing studies with positive results while rejecting those with negative ones. According to the Catalogue of Bias, a database that defines and lists examples of more than 10 different types of biases in health sciences, publication bias happens “when the likelihood of a study being published is affected by the findings of the study.” In a variant form, publication bias favors publication of papers distorted by spin that impacts their findings or interpretations. Spin might include manipulation of figures, selective reporting of outcomes, among others.