PROJECT SUMMARY/ABSTRACT Education is among the most important predictors of cognitive functioning and cognitive impairment (including MCI and AD/ADRD). However, because scientists do not know how or why education matters for these cognitive outcomes, it is difficult to design effective interventions. There is currently very little information about (a) the specific aspects of education that prevent or provide resilience to cognitive impairment and (b) the pathways through which those effects operate. A major reason for this lack of information about how or why education matters for these cognitive outcomes is that data on educational opportunities, environments, and attainments have mainly been gathered via retrospective reports. To know how and why education matters for cognitive functioning and impairment, the scientific community needs high quality prospective studies that follow young people through schools and throughout adulthood, measures key and modifiable aspects of education, and then assess cognitive functioning later in life. This project brings together an interdisciplinary team of leading neurologists, neuropsychologists, sociologists, education scientists, and survey methodologists who will design protocols to re-contact all ≈25,500 surviving members the High School & Beyond (HSB) cohort—a nationally representative random sample of Americans first interviewed in high school in 1980—and use the resulting data to conduct transformative analyses of the effects of education on cognitive function and risk for impairment at midlife. The project has five aims: (Aim 1) To estimate the effects of (a) adolescent cognitive and non-cognitive skills, (b) secondary school course taking and college field of study, and (c) other school structures and social environments on cognitive functioning and impairment at midlife; (Aim 2) To assess the degree to which racial/ethnic differences in those aspects of education explain racial/ethnic disparities in cognitive functioning and impairment; (Aim 3) To assess the degree to which the effects of education are mediated by educational attainment, economic strain, and the cognitive complexity of paid jobs at midlife; and (Aim 4) To assess the degree to which race/ethnicity and genetic risk factors moderate the effects of education on cognitive functioning and impairment. To gather the data required to pursue these Aims, the investigators will conduct an internet/phone survey and gather genetic material via a mail-back saliva kit. (Aim5) The resulting database and associated documentation and metadata will be made freely available to the research community to facilitate scholarship on the development of MCI, AD/ADRD, and cognitive decline.