Operation Research (OR) and Management Sciences (MS) are the professional discipline that deal with the application of information technology and mathematics for informed decision-making.

OR/MS Professionals aim to provide rational bases for decision making by seeking to understand and structure complex situations and to use this understanding to predict system's behavior and improve system's performances.

Much of this work is done by using analytical and numerical techniques to develop and manipulate mathematical and computer models of organizational systems composed of people, machines, and procedures.

OR/MS draws upon ideas from engineering, management and mathematics to contribute to a wide variety of application domains; the fields is closely related to several other fields in the "decision sciences" - applied mathematics, computer science, economics, industrial engineering, and systems engineering.

A rough distinction between OR and MS is that OR is "theory-oriented" whereas MS is "application-oriented". In Italy the two aspects live togheter within a unique discipline called "Ricerca Opertativa".