Assessing the validity of a vulnerable population is specifically difficult with no generalized measures existing to evaluate the legitimacy of using the so-called “special groups” in research. The main issue related to utilizing vulnerable population in research is limited population validity. Population validity is defined as a type of external validity, signifying the extent to which the results derived from the sample can be extrapolated to the entire population or its large segments (Arias et al., 2015). With a high susceptibility to the risks of participating in a study, vulnerable populations generally do not demonstrate results that are easily generalized even to the specific segment representing a “special group.”
There is a number of reasons that contribute to the decreased validity of a vulnerable population. First, it is essential to consider the selection bias, which refers to the distinctions between groups in a research that may be associated with the independent variable (Bracken-Rochel et al., 2017). Selection bias is strengthened with the distorted motivation and willingness of the respondents to take part in the study, as well as specific demographic characteristics that influence one’s ability to make autonomous decisions.
Second, the validity is limited with the sample features, particular to the situation, location, and other individual measures that may impact the results of the study yet fail to produce generalized findings (Quinn, 2015). Examples of such can be research based on prison inmates or geriatric patients in the residential facilities, where study results are highly affected by the participants’ restricted freedom of movement. Consequently, to ensure the validity of the vulnerable population sample, it is vital to pay close attention to the selection bias and situational sample features.
References
Arias, J. J., Pham-Kanter, G., Gonzalez, R., & Campbell, E. G. (2015). Trust, vulnerable populations, and genetic data sharing. Journal of Law and the Biosciences, 2(3), 747-753. Web.
Bracken-Rochel, D., Bell, E., Macdonald, M. E., & Racinel, E. (2017). The concept of ‘vulnerability’ in research ethics: An in-depth analysis of policies and guidelines. Health Research Policy & Systems, 15(8), 1-18. Web.
Quinn, C. R. (2015). General considerations for research with vulnerable populations: Ten lessons for success. Health & Justice, 3(1), 1-7. Web.