Operations research (OR) and management science are terms that are used interchangeably to describe the discipline of applying quantitative techniques to make decisions and solve problems. Many methods used in operations research were developed during World War II to help take the guesswork out of missions such as deploying radar, searching for enemy submarines, and getting supplies where they were most needed. Following the war, numerous peacetime applications emerged, leading to the use of OR and management science in many industries and occupations.

Synonyms: Operational Research, MS (management science), OR + MS = ORMS, IE (industrial Engineering), DS (Decision Science