Hagan et al. refers to a group of researchers led by Hagan who conducted a study or published a paper on a specific topic. Their work often contributes to the fields of sociology, psychology, or public policy, providing insights based on empirical data and analysis. The findings from Hagan et al. are typically used to inform practices, policies, or further research. Their studies may explore issues such as crime, education, or social behavior, aiming to enhance understanding and address societal challenges.