INVESTIGATOR BIAS:
A general term that describes any biases on the part of the investigator in a research study, towards a particular result(s), scientific procedure(s), or interpretation(s) of findings1,2. Investigator Bias may arise due to conflicts of interest, moral or political leanings, preconceived opinions or notions, or personal characteristics of the investigator.
Arguably, Investigator Bias cannot be completely avoided in any study, as no human is completely unbiased (see Bias (Definition)). However, using strategies such as blinding of recruitment/selection of participants, exposure assignment, data collection, and analysis may help to mitigate this bias. Further, peer-review, and the use of independent expert and non-expert panels may help to identify Investigator Biases if they are present. Also see: Bias Due to Conflicts of Interest, Cognitive Dissonance Bias, Confirmation Bias, Disconfirmation Bias, Interpretive Bias, and Rescue Bias.
References:
1. Porta M, ed. A Dictionary of Epidemiology. Sixth ed. New York, NY: Oxford University Press 2014. (Link to Reference)
2. Ernst E, Canter PH. Investigator bias and false positive findings in medical research. Trends Pharmacol Sci. 2003;24(5):219-21. (Link to Reference)