Elsevier

The Journal of Pain

Volume 19, Issue 7, July 2018, Pages 787-796
The Journal of Pain

Pain, Please: An Investigation of Sampling Bias in Pain Research

https://doi.org/10.1016/j.jpain.2018.02.011Get rights and content
Under an Elsevier user license
open archive

Highlights

  • Experimental pain research may be especially susceptible to sampling bias.

  • Fear of pain was associated with perceived likelihood of participation.

  • Sensation-seeking was associated with participation in experimental pain research.

  • Sampling bias can threaten the validity and generalizability of pain research.

Abstract

Experimental pain research frequently relies on the recruitment of volunteers. However, because experimental pain research often involves unpleasant and painful sensations, it may be especially susceptible to sampling bias. That is, volunteers in experimental pain research might differ from nonvolunteers on several relevant variables that could affect the generalizability and external validity of the research. We conducted 2 studies to investigate potential sampling bias in experimental pain research. In study 1 we assessed participants' (N = 275; age = 17–30 years) perceived likelihood of participating in pain research. Pain catastrophizing, fear of pain, illness and injury sensitivity, depression, anxiety, sensation-seeking, gender identity, body appreciation, and social desirability were also assessed as potential predictors of the likelihood to participate. In study 2, participants (N = 87; Age = 18–31 years) could sign up for 2 nearly identical studies, with only one involving painful sensations. Thirty-six participants signed up for the pain study and 51 participants signed up for the no-pain study. Study 1 showed that lower levels of fear of pain, higher levels of sensation-seeking, and older age predicted the perceived likelihood of participating in pain research. Study 2 showed significantly higher levels of sensation-seeking in participants who signed up for the pain study compared with those who signed up for the no-pain study. The implications of these findings for future research, as well as the clinical conclusions on the basis of experimental pain research, are discussed.

Perspective

Intention to participate in experimental pain research was associated with less fear of pain, higher sensation-seeking, and older age. Actual participation in experimental pain research was associated with higher sensation-seeking. This potential sampling bias in studies involving painful stimuli could limit external validity and generalizability of pain research.

Key words

Pain research
sampling bias
volunteer bias
external validity
generalizability

Cited by (0)

Conflicts of interest: K.K. is a doctoral researcher of the Research Foundation Flanders (FWO) Vlaanderen, Flanders, Belgium (grant ID 1111015N). Further, the contribution of J.M.A. was supported by Netherlands Organisation for Scientific Research (NWO) Grant 446-15-011.

The authors have no conflicts of interest to declare.

Supplementary data accompanying this article are available online at www.jpain.org and www.sciencedirect.com.