Observer effect

Observers tend to influence what they are observing, and this needs to be considered when deciding on the most suitable kind of observer role a researcher should take in a particular study.

Now please wash your hands...

"There are additional sources of error with observational studies. If persons of interest are asked for consent prior to observation, then those whose HH [hand hygiene] is extremely poor may avoid participating in the study, which may bias the results. If overt observation is used, then people may change their behavior when they know they are being observed." (van de Mortel & Murgo, 2006: 98)

van de Mortel, T., & Murgo, M. (2006). An examination of covert observation and solution audit as tools to measure the success of hand hygiene interventions. American Journal of Infection Control, 34(3), 95-99. doi: http://dx.doi.org/10.1016/j.ajic.2005.07.006

“Women were observed after elimination in a public restroom to determine the effects of the presence or absence of an observer upon the likelihood of handwashing. 18 of 20 [90%] subjects in the presence of another and 3 of 19 [16%] who were not observed washed. The difference in frequency of handwashing between the two groups was clearly significant.” (Abstract, Pedersen, Keithly & Brady, 1986)

Pedersen, D. M., Keithly, S., & Brady, K. (1986). Effects of an observer on conformity to handwashing norm. Perceptual and Motor Skills, 62(1), 169-170. doi: 10.2466/pms.1986.62.1.169

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