Observer effect

A topic in research methodology

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

Naturalistic research seeks to avoid intervening in the situation being researched, but how can we know we are observing the 'natural' (normal) state of things if people know we are observing them?

Covert observation (where those being observed are not aware that the observation is taking place) usually raises ethical issues, but may sometimes be considered as the only option for observing normal behaviour

Now please wash your hands…

This is how some researchers justified not seeking voluntary informed consent which research handwashing behaviour in medical contexts,

"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

Does this seem a convincing argument, or does it seem a somewhat cynical suggestion? If it seems that van de Mortel & Murgo were overestimating the observer effect, then consider this study:

“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 [sic, knowingly!] washed. The difference in frequency of handwashing between the two groups was clearly significant.”

Pedersen, Keithly & Brady, 1986: 169

Sources cited:

• 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
• 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