Psychology Ph.D. Dissertations

Developing a Health Numeracy Scale to Assess Medical Decision Making Among Older Adults

Date of Award


Document Type


Degree Name

Doctor of Philosophy (Ph.D.)



First Advisor

Yiwei Chen (Committee Chair)

Second Advisor

Richard Anderson (Committee Member)

Third Advisor

Scott Highhouse (Committee Member)

Fourth Advisor

James Foust (Other)


Physical and cognitive decline in late adulthood is considered a normative change of aging. Consequently, the ability to make sound decisions regarding medical matters becomes an important factor in older adults’ well-being. As health information is often presented numerically, the ability to work with such information (health numeracy) is extremely important for making medical decisions (e.g., choosing a Medicare plan). While general numeracy has gained attention from aging and decision making researchers, the construct of health numeracy and its relationships with general numeracy and medical decision making were rarely studied. In Study 1, a measurement of health numeracy was developed and validated through an online sample (N = 262). Then the scale was refined through a Rasch analysis. In Study 2, the newly developed Health Numeracy Scale was cross validated in a community sample (N = 108). Regression analyses indicated that health numeracy was a more suitable predictor over general numeracy in predicting medical decision making in older adults. Implication and future directions of the findings were discussed.