Scientific literacy is an important educational and societal goal. Measuring scientific literacy, however, has been problematic because there is no consensus regarding the meaning of scientific literacy. Most definitions focus on the content and processes of major science disciplines, ignoring social factors and citizens’ needs. The authors developed a definition of scientific literacy for the California 4-H Program from the citizen’s perspective, concentrating on real-world science-related situations. The definition includes four anchor points: science content; scientific reasoning skills