Strange things statistics.

At first sight, Rescuecom's latest ratings on reliability of computer models seems to give a snap judgment as to which computers are performing well and which are duds. Certainly, the rapid decline in the ratings for Asus should cause a few frowns of concern in the purlieus of Seoul and the top marks for Apple should provide smiles all round at Apple HQ.

But there's more to this than meets the eye. The Rescuecom ratings are based on a very crude measure - matching up US market share with the number of support calls received. That's a very crude measure however. The IDC figures that Recuecom uses covers the whole of the US, every industrial sector and every type of market -  it could well be that Rescuecom has a customer base that's heavily PC-dependent. 

It also doesn't take into account the type of customer; maybe the Macs are bought by users who are a bit more educated and a bit more tech-savvy, in other words,  people who are more able to fix their own faults. Again, that would skew the results considerably.

Nor is the age of the machines taken into account - it could well be that Mac users renew their machines more often - although it seems as if the sudden influx of Asus PCs counted against the Korean company. Nor do we know what applications are running on the machines and whether the underlying software was causing problems. 

We don't know of course, what the figures would be if Rescuecom took a more accurate approach to assessing market share - it could be that Apple would have even better ratings.

What instructive, however, is that there are so little guides to computer reliability. We have covered Rescuecom's figures in Techworld on a number of occasions - and will do so again - because they offer one of the few assessments of machine stability. Lab tests, which by their nature are short-term, offer little guidance as to how machines will behave day after day in the hands of a non-expert user.

In some ways this is good - it shows that PCs are now, whoever the manufacturer, incredibly stable machines and anyone buying a personal computer will be guaranteed some level of performance but for those people who want more than the basic level, it would be useful to have more accurate figures.

Two cheers to Rescuecom for its efforts then but perhaps some refinement next time to get really accurate readings.