One can debate the optimum number of beds required for a sleek but dependable national health service.

ECONOMIST: The health service

During the war he crunched numbers for his country, calculating the optimum number of pellets in anti-aircraft shells.

ECONOMIST: Milton Friedman

Prof McAllister credited Mr Hughes with the ability to channel an athlete's talents into the optimum number of sports, in turn increasing the medal-winning opportunities for Wales.

BBC: Paralympics: Coaches in Wales behind disabled sport elite