Efforts by policymakers to involve patients in treatment decision making are increasing worldwide. Some of these efforts must accommodate patients with different levels of health literacy, but do not specify if numeracy is part of health literacy. This research asked, How are health literacy and numeracy defined in the academic literature and what empirical relationship(s) do they have with the three stages of the treatment decision making process? I conducted a systematic review and two scoping reviews. In the systematic review, I identify definitions of health literacy used in the academic literature and interpretations possible for the most commonly used definitions. In the first scoping review, I map the empirical relationships between health literacy and the three stages of treatment decision making (information exchange, deliberation, and deciding on the treatment to implement). In the second scoping review, I map the empirical relationships between numeracy and the three stages of treatment decision making, and examine if, and how, numeracy has been mentioned in relation to health literacy. The systematic review identified 250 different definitions of health literacy and found the most commonly used definitions open to differing interpretations. The scoping reviews revealed a lack of: (1) agreement over the definition, measurement, and handling of health literacy and numeracy in studies, and (2) overlap in the relationship(s) examined. Health literacy and numeracy were largely treated as separate concepts. Knowledge gaps and measurement-related problems were identified. The findings from the systematic review pose significant challenges for the measurement of health literacy and for the implementation of health literacy-related policy initiatives. The meaning(s) of health literacy must be explicated by both researchers and policymakers. The findings from the scoping reviews indicate that the relationship(s) between health literacy, numeracy, and treatment decision making is unclear. Researchers must address the knowledge gaps and measurement-related problems identified.

Health literacy – the ability to obtain, understand, evaluate, and communicate information - is gaining increasing attention from both researchers and policymakers. This attention is important to efforts seeking to involve patients in their treatment decisions. Some of these efforts require attention to patients’ health literacy, but do not make clear if numeracy (or math skills) is part of health literacy. This research examines how health literacy and numeracy are defined. The relationship(s) that health literacy and numeracy have with the three stages of the treatment decision making process are also examined. The findings show that health literacy and numeracy have been: (1) defined and measured differently in studies, and (2) largely treated as separate concepts by researchers. The relationships between health literacy, numeracy, and the three stages of treatment decision making are also unclear because of knowledge gaps and measurement-related problems.

Doctor of Philosophy (PhD)

Dissertation