Evidence of experimental bias in the life sciences: why we need blind data recording

Holman, Luke; Head, Megan L.; Lanfear, Robert; Jennions, Michael D.

Abstract

Observer bias and other “experimenter effects” occur when researchers’ expectations influence study outcome. These biases are strongest when researchers expect a particular result, are measuring subjective variables, and have an incentive to produce data that confirm predictions. To minimize bias, it is good practice to work “blind,” meaning that experimenters are unaware of the identity or treatment group of their subjects while conducting research. Here, using text mining and a literature review, we find evidence that blind protocols are uncommon in the life sciences and that nonblind studies tend to report higher effect sizes and more significant p-values. We discuss methods to minimize bias and urge researchers, editors, and peer reviewers to keep blind protocols in mind.

Citation

Holman, L., Head, M. L., Lanfear, R., & Jennions, M. D. (2015). Evidence of experimental bias in the life sciences: why we need blind data recording. PLOS Biology, 13(7), Article e1002190. https://doi.org/10.1371/journal.pbio.1002190

• Journal Article Type: Commentary
• Online Publication Date: Jul 8, 2015
• Publication Date: 2015
• Deposit Date: Feb 17, 2021
• Publicly Available Date: Feb 19, 2021
• Journal: PLOS Biology
• Print ISSN: 1545-7885
• Publisher: Public Library of Science
• Peer Reviewed: Peer Reviewed
• Volume: 13
• Issue: 7
• Article Number: e1002190
• DOI: https://doi.org/10.1371/journal.pbio.1002190
• Public URL: http://researchrepository.napier.ac.uk/Output/2722845