The Influence of Locus of Control on the Uptakes of Cancer Screening: Evidence from the United States

This study utilizes eight waves of the US Health and Retirement Study (HRS) and its "Leave-Behind" module
(2006–2020) to explore the extent to which Locus of Control (LoC) influences the uptake of breast and prostate
cancer screening. While traditional socioeconomic factors only partially explain variations in preventive care,
recent literature suggests that psychological traits can play a pivotal role in health investments. We focus on
the role of LoC - the degree to which individuals believe they can control life outcomes through their own
actions - investigating how this trait interacts with the different institutional frameworks governing cancer
detection in the United States.
The empirical analysis focuses on a longitudinal sample of individuals living in the US, residing in partnered
households and aged 50 and older. We employ a dynamic panel data model with Mundlak corrections to
account for time-invariant unobserved heterogeneity and behavioural persistence. The baseline model is
estimated using GSEM, which allows clustering at the household level to account for the interdependence of
health decisions between partners. The dependent variables are two binary variables, which are equal to 1 if
the individual has undergone breast/prostate cancer screening in the last two years, 0 otherwise. The key
independent variable is LoC, assessed using a six-point Likert scale.
Our findings reveal a significant gender divergence: while internal LoC has a positive and robust effect on the
likelihood of undergoing prostate cancer screening, its influence on breast cancer screening is negligible. This
suggests that psychological agency is a critical determinant in contexts of clinical ambiguity and "shared
decision-making" (as seen in prostate-specific antigen - PSA testing for prostate cancer, USPSTF Grade C),
whereas institutionalized routines (such as mammography for breast cancer, USPSTF Grade B) effectively
bypass individual psychological predispositions. These results offer relevant insights for designing public
health interventions that account for the intersection between personality traits and institutional designs.