Operational research aims to apply analytical methods to improve decision-making and resource allocation in various fields, including health care. It originated during World War II to study military problems scientifically. Now, operational research techniques are used to identify issues in health programs, test solutions to address those issues, and evaluate changes made to programs. The goal is to generate practical evidence to improve implementation, effectiveness, efficiency and sustainability of programs. Common methods include simulation, optimization, and data analysis. Operational research requires collaboration between managers and researchers throughout the research process.