Date of Award

Summer 8-2021

Author's School

Graduate School of Arts and Sciences

Author's Department


Degree Name

Master of Arts (AM/MA)

Degree Type



Within the United States, many large-scale, nationally representative studies exist with the goal of tracking and monitoring aspects of health. These studies are often used to establish the prevalence of dementia and subjective cognitive decline (SCD) in the population. The goal of the current study is to examine how different population-based studies probe respondents about conditions related to cognitive impairment, and to assess similarities and differences in point estimates. We reviewed eight studies and identified comparable items related to dementia and SCD. We calculated design-appropriate point prevalence estimates and compared weighted estimates across studies, finding a wide range and statistically significantly different estimates for dementia (estimates ranging from 2.7% - 9.9%) and for SCD (5.6% - 46.6%). Close analysis of item construction revealed meaningful differences in the use of terminologies and timeframes that could account for these differences. Moreover, subtle but consequential sampling differences were also discovered within study documentation that also could be responsible. Given the importance of prevalence estimates for research, practice, and policy, our findings highlight the need for harmonization across methodology in these large studies, even at their most basic level, to establish the true burden of these conditions.


English (en)

Chair and Committee

Brian D. Carpenter

Committee Members

Patrick Hill Denise Head