The USC Dornsife Center for Self-Report Science (CSS) improves our understanding of how people answer questions about themselves and develops innovative methods that provide accurate, reliable, and ecologically valid self-reports. Faculty investigate the range of sampling densities from high frequency self-report data in people’s natural environments using ecological momentary assessment, through daily diaries, day reconstruction methods, and traditional recall assessments. Personnel have expertise in content domains, such as subjective well-being, fatigue, pain, and other aspects of people’s health that are common foci of science and medical practice.