3 AUGUST 2002, Page 15

Mind your language

AT last it is sorted out. Step change, I mean; a term recently used optimistically by both Mr Gordon Brown and Mr John Prescott.

I had looked in some dictionaries and found step function and step unit, but not step change. Then Air Chief Marshal Sir John Barraclough kindly wrote to say it belonged to the world of statistical analysis. 'It is used to describe the move of a function to a new order rather than to a further degree of its old one. The imagery of the term is easy to assimilate if you think of it in graph form: from a gentle incline over a period of time we suddenly have to move the graph line vertically to represent this new data.' Yes, I see.

Mr Alastair Howatson wrote from Oxford to explain that in the 19th century Oliver Heaviside 'defined a unit function to represent mathematically any quantity that changed suddenly from zero to the value one. Later it became known (probably in America first of all) as a unit step function. It is also known simply as a unit step, and a similar change to a value other than one is in general a step function or even just step. These last two appear in the Shorter Oxford Dictionary (1993)'. Yes, perhaps so, but the New Oxford Dictionary of English (the Node), 1998, merely has: 'step: Physics, an abrupt change in the value of a quantity, especially voltage'. Who mentioned physics?

Mr Mike Pollard wrote to say that 'step change is an investment term'. And I think he is right, too. His point is that with a lump of investment one can make, say, nine widgets; if you want to make ten widgets, you need another lump of investment — but then you can make anything between ten and nineteen widgets before another step up is required.

Mr Pollard suggests how the term fell into the speechwriter's vocabulary, 'Over the last three or four years,' he says, 'the term has been hijacked by management and humanresources pundits. Thus step change has become synonymous with major or significant change.' So, for politicians it has become a hooray-word.

A footnote. The term has nothing to do with changing step; but if so many of you thought it did, Messrs Brown and Prescott cannot be communicating very well by using it all the time.

Dot Wordsworth