Racial, Ethnic, and Geographic Diversity in Population Neuroscience

Abstract

In this chapter, we consider lack of racial, ethnic, and geographic diversity in research studies from a public health perspective in which representation of a target population is critical. We review the state of the research field with respect to racial, ethnic, and geographic diversity in study participants. We next focus on key factors which can arise from the lack of diversity and can negatively impact external validity. Finally, we argue that the public's health, and future research, will ultimately be served by approaches from both recruitment and representation science and population neuroscience, and we close with recommendations from these two fields to improve diversity in studies.

Keywords: Alzheimer’s disease and related dementias; External validity; Public health; Recruitment and representation science; Representativeness.

Fig 1.. Examples of problems arising from lack of diversity.

Top left: The exposure-outcome relationship varies by sex assigned at birth, and the sample has a greater proportion of male participants than the target population. Bottom left: An activities of daily living measure works differently in men vs. women. Top right: The exposure-outcome association is strong in the sample, but not in the target population due to differing ranges of exposure values in the sample vs. target population. Bottom right: The sample has a greater proportion of participants with high education (aqua) than the target population.

Fig 2.. Non-linearities and range effects.

Samples drawn from populations in the red areas (top and bottom of the sigmoid) would have no association between exposure and outcome whereas samples drawn from populations in the green area (middle of the sigmoid) would have a strong positive correlation between exposure and outcome.