It is time to face up to "hedonic regression". It has been with us for more than a decade sometimes under different names, or none at all.

It looms larger in our lives month by month. It is used to measure the buying power of our money and indirectly as a factor in the management of our economy.

Some readers of this column, like its author, may have wondered what on earth the words mean, if anything. In the ancient Greek I was taught to no particular effect more than half a century ago, I think there was a word like "hedos" meaning pleasure. Anyway modern hedonists are people who behave badly in the mindless pursuit of enjoyment.

"Regression" means going backwards. So hedonic regression should be about retreating pleasurably, getting a thrill out of driving in reverse, perhaps.

Not so. It happens when you buy a digital camera or a laptop with more bells and whistles than last year's model, or a car with climate control instead of steam-age air-conditioning, but the price is the same, or even less.

You have more to enjoy at no extra cost. Nobody pauses to wonder if a mobile phone incorporating a video camera is more enjoyable than one without. That depends on whether you want to send video sequences by mobile.

The idea is that you get more for your money so you can afford the hefty sums that the mobile company charges people who send video clips.

To a statistician, the price has fallen - gone backwards - and that is that. Inflation is less than it would be otherwise.

That is the theory. The clever people who adjust the indices to measure inflation every February are using it more and more "to produce valuations of changes in quality".

If they didn't the cost of goods, though not services, couldn't possibly be less than this time last year. At the end of it, inflation comes out lower and so, other things being equal, do interest rates. That is the hedonic bit.