Chavalariasab D, Ioannidis JPA. Science mapping analysis characterizes 235 biases in biomedical research. Journal of Clinical Epidemiology 2010;63(11):1205-1215. (doi:10.1016/j.jclinepi.2009.12.011)
There are many different types of bias in medical research and publishing. This systematic mapping analysis of over 17 million articles from PubMed found 235 bias terms and 103 other terms used commonly in articles about bias. Forty terms were used in the title or abstract of more than 100 articles each. Clusters of terms were organized into macroscopic maps showing the distribution of bias types. Some bias tems (e.g. confounding, selection bias, response bias, publication bias) show increased use over time.