A scoping review of Table 2 fallacy in the oral health literature

Background Coined by Westreich and Greenland in 2013, Table 2 fallacy refers to the practice of reporting estimates of the primary exposure and adjustment covariates derived from a single model on the same table. This study seeks to describe the extent to which Table 2 fallacy is present in the oral health literature and provide recommendations on presenting findings from multivariable‐adjusted models and/or interpretation of adjustment covariate estimates that are not the primary exposure. Methods We conducted a scoping review in PubMed and Scopus of human observational studies published in 4 oral health journals (JDR‐CTR, CDOE, JPHD, BMC Oral Health) starting in 2013 until the end of 2018. The resulting articles were exported into Excel and were either included or excluded for full‐text review based on six criteria. After categorizing the articles, we exported and summarized the results in SAS. Results A total of 1358 articles were initially screened of which 937 articles were excluded based on title or for being animal studies, systematic reviews or meta‐analysis, prediction models or descriptive studies. The remaining 421 articles were eligible for full text reviewed of which, 189 (45%) committed Table 2 fallacy. The prevalence of table 2 fallacy appears high in the oral health literature. Conclusions The problem of presenting multiple effect estimates derived from a single model in the same table is that it inadvertently encourages the reader to interpret all estimates the same way, often as total effects. Implications and recommendations are discussed.