Life is changing for the car price guides.

For one thing their customers do not need them as badly as they used to. For another: data is more plentiful, more readily available, and has to be assembled better to provide value.

But let’s start with the piece of data that lets all hell loose: Question to AM readers in a recent survey: “Do the used car price guides help you keep on top of profitability in used cars? Answer: 66.2% No; 33.8% Yes.

“Staggering! 66.2%? Unbelievable,” responded Adrian Rushmore, a doyen of the data crunchers. Rushmore runs the processes at Glass’s Guide and has done so for longer than he cares to remember.

Once order is restored, Rushmore applies analysis to the trends of the last few years: “I would accept that compared to 10 years ago we, the price guides, are less vital in informing a decision.

"But what we do is to provide a benchmark from which a decision is made.”

Free electronic information is at the heart of the change, nibbling away at the supremacy and secrecy enjoyed for so long by Glass’s and CAP.

A quick look at cars advertised on the internet gives a pretty clear idea of an average asking price for any model. Once you have that, subtract the margin and get the purchase price.

However scientific the price guides become, basic info is there for nothing.

Rushmore is hard at work refining the quality of his product and its accessibility.

With more data available, processing more, offering more and making it available faster is the rationale.

The latest initiative offers auction data – previously released monthly – daily on the web.

That regularity means not only spot prices but momentum as well.

The vehicles in demand will be seen creeping up in price as demand grows.

“This is helpful to us. Dealers are expecting more and we will deliver more.”

It is estimated that 9% of the trade uses one or more of the guides.

They do so in a robust manner – frequently criticising opinions that do not marry up with personal experience.

The criticism is welcome; it proves that they are still followed and valued.

Glass’s will do portfolio valuations for customers. The car retailers are very happy to sub-let that job as it is so laborious to check

“It is a very unwieldy task to have to go through all the valuations for all the Ford Focus derivatives in stock. We have a tool that allows us to help the process.”