With the amount of health information increasing, health literacy has become progressively more important for public health. Patients are struggling to be more informed consumers as they navigate a complex health care system and are seeking health information from a variety of sources. There are large discrepancies in terms of who receives health information and how it impacts their lives and their health. Research is needed to understand the relationships between health information, health literacy, and health outcomes. Prior studies have found that lower literacy is associated lower health knowledge, suboptimal use of preventive health services, poorer intermediate disease markers, and increased incidence of chronic illness. Recent estimates indicate that approximately 90 million adults in the U.S. have limited literacy skills. While the metaphor of "literacy" focuses us on language skills, health literacy is actually a multidimensional construct with at least the following elements: functional literacy, document literacy, verbal competency, and numeracy. Unfortunately, leading instruments such as the Wide Range Achievement Test (WRAT) reading subtest, the Rapid Estimate of Adult Literacy in Medicine (REALM), and the Test of Functional Health Literacy in Adults (TOFHLA) actually measure reading ability and ignore these other dimensions. As a result, studies of health literacy may not have maximized their potential, and this, perhaps, is reflected in the inconsistency of research findings. Accordingly, the specific aims of this study are to (1) develop a pool of survey items that reflect an operational definition and conceptual framework for health literacy using an expert consensus process, (2) ensure the functionality of the items by pretesting them using cognitive appraisal methodology, (3) pilot test the items with individuals at a variety of reading and educational levels, and (4) assess the psychometric properties of the health literacy items and examine their relationship with selected health outcomes including utilization of health care services. This study presents a unique opportunity to advance the field of health literacy by developing more comprehensive and better measures that can be used to establish baseline levels and monitor population-level changes over time. Government agencies, researchers, and others can use these measures to assess the relationship with health outcomes. The project is responsive to several of the recommendations outlined in the Institute of Medicine's book Health Literacy: A Prescription to End Confusion, in particular its call to develop and test new measures of health literacy and to field them as part of large ongoing population surveys.