Assessing Citation Bias in Scientific Literature |Biomedgrid

Our objective was to provide a further test of possible citation bias or confirmation bias in science based on differential outcomes of two articles published between 1979 and 2013. The two articles used here formed a natural experiment because the articles were from the same author and concerned similar topics except one article had more positive results for its participants. Based on Google Scholar citations, citation rates were compared using binomial tests, including normal approximation z scores, and one-sample chi-square tests. Between the two articles, the one that presented more favorable findings was cited far more often than the one with less positive results, providing empirical support for the existence of citation or confirmation bias, which may result in lower quality and less comprehensive literature reviews.