Its first chairman was Sir Owen Wansbrough-Jones, and the first hon secretary at that time was Pat Rivett. By 1955 interest in Operational Research had spread to most western countries. Membership of the Society plateaued at around 3,000 in the early seventies and has remained at roughly the same level ever since. Professor P.M.S. Blackett was one of the first scientists to define the essential elements of Operational Research. In October 1941 he wrote a Report on Operational Research which is considered by many to be the original 'definition of Operational Research'.
Operational staff provide the scientists with the operational outlook and data.
The scientists apply scientific methods of analysis to this data, and are thus able to give useful advice. A year later Sir Charles Goodeve summed it up as 'quantitative common-sense' . Nowadays the OR Society steers clear of formal definitions, preferring to illustrate what OR does by means of examples. Today the Society has over 3000 members in 53 countries who receive a wide range of services and benefits. The Society's training programme is the most comprehensive OR training programme on offer anywhere in the world.