Self-selection biases in psychological studies: Personality and affective disorders are prevalent among participants

Authors: Kaźmierczak, I., Zajenkowska, A., Rogoza, R., Jonason, P. K., & Ścigała, D.

Abstract

Respondents self-select the psychological studies they wish to participate in based on their needs and characteristics, inadvertently introducing a self-selection bias. The question arises whether individuals drawn to psychological studies exhibit higher rates of psychological dysfunctions, such as personality and affective disorders, compared to the general population. We examined whether the nature of the invitation (discussing recent critical or regular life events) or the data source (face-to-face or online) attracts individuals with varying levels of psychopathology (N = 947; 62% women). Significantly, participants who specifically applied for paid psychological studies displayed more symptoms of personality disorders than those who had not previously applied for such studies. These findings strongly suggest a need to either adjust recruitment strategies or exercise greater caution when generalizing results due to this methodological concern.