Lord Kelvin many years ago expounded his oft-quoted dictum, ‘When you can measure what you are speaking of, and express it in numbers, you know that on which you are discoursing. But when you cannot measure it or express it in numbers, your knowledge is of a meagre and unsatisfactory kind.’ Operational Research is primarily concerned with measurement in management.

Unit trusts originated in the United Kingdom in the second half of the nineteenth century, but an early court ruling that unit trusts were not legal resulted in all but one unit trust changing to the form of investment trusts. Although the court ruling was later reversed, little further headway was made by the unit trust movement until after the Great Crash of 1929.