Observer bias

Observer bias is one of the types of detection bias and is defined as any kind of systematic divergence from accurate facts during observation and the recording of data and information in studies.[1] The definition can be further expanded upon to include the systematic difference between what is observed due to variation in observers, and what the true value is.[2]

Observer bias is the tendency of observers to not see what is there, but instead to see what they expect or want to see. This is a common occurrence in the everyday lives of many and is a significant problem that is sometimes encountered in scientific research and studies.[3] Observation is critical to scientific research and activity, and as such, observer bias may be as well.[4] When such biases exist, scientific studies can result in an over- or underestimation of what is true and accurate, which compromises the validity of the findings and results of the study, even if all other designs and procedures in the study were appropriate.[5]

Observational data forms the foundation of a significant body of knowledge. Observation is a method of data collection and falls into the category of qualitative research techniques. There are a number of benefits of observation, including its simplicity as a data collection method and its usefulness for hypotheses. Simultaneously, there are many limitations and disadvantages in the observation process, including the potential lack of reliability, poor validity, and faulty perception. Participants' observations are widely used in sociological and anthropological studies, while systematic observation is used where researchers need to collect data without participants direct interactions. The most common observation method is naturalistic observation, where subjects are observed in their natural environments with the goal to assess the behaviour in an intervention free and natural setting.

Observer bias is especially probable when the investigator or researcher has vested interests in the outcome of the research or has strong preconceptions. Coupled with ambiguous underlying data and a subjective scoring method, these three factors contribute heavily to the incidence of observer bias.[6]

  1. ^ Mahtani, Kamal; Spencer, Elizabeth A.; Brassey, Jon; Heneghan, Carl (2018-02-01). "Catalogue of bias: observer bias". BMJ Evidence-Based Medicine. 23 (1): 23–24. doi:10.1136/ebmed-2017-110884. ISSN 2515-446X. PMID 29367322. S2CID 46794082.
  2. ^ Miettinen, Olli S. (2008-11-01). "M. Porta, S. Greenland & J. M. Last (eds): A Dictionary of Epidemiology. A Handbook Sponsored by the I.E.A.". European Journal of Epidemiology. 23 (12): 813–817. doi:10.1007/s10654-008-9296-5. ISSN 0393-2990. S2CID 41169767.
  3. ^ Pronin, Emily (2007-01-01). "Perception and misperception of bias in human judgment". Trends in Cognitive Sciences. 11 (1): 37–43. doi:10.1016/j.tics.2006.11.001. ISSN 1364-6613. PMID 17129749. S2CID 2754235.
  4. ^ Hróbjartsson, Asbjørn; Thomsen, Ann Sofia Skou; Emanuelsson, Frida; Tendal, Britta; Hilden, Jørgen; Boutron, Isabelle; Ravaud, Philippe; Brorson, Stig (2012-02-27). "Observer bias in randomised clinical trials with binary outcomes: systematic review of trials with both blinded and non-blinded outcome assessors". BMJ. 344: e1119. doi:10.1136/bmj.e1119. ISSN 0959-8138. PMID 22371859. S2CID 23296493.
  5. ^ Tripepi, Giovanni; Jager, Kitty J.; Dekker, Friedo W.; Zoccali, Carmine (2010). "Selection Bias and Information Bias in Clinical Research". Nephron Clinical Practice. 115 (2): c94–c99. doi:10.1159/000312871. ISSN 1660-2110. PMID 20407272. S2CID 18856450.
  6. ^ Tuyttens, F. A. M.; de Graaf, S.; Heerkens, J. L. T.; Jacobs, L.; Nalon, E.; Ott, S.; Stadig, L.; Van Laer, E.; Ampe, B. (2014-04-01). "Observer bias in animal behaviour research: can we believe what we score, if we score what we believe?". Animal Behaviour. 90: 273–280. doi:10.1016/j.anbehav.2014.02.007. ISSN 0003-3472. S2CID 53195951.