One reason cited for the extreme volatility on Wall Street of late is a lack of clarity for US companies' future earnings.

"How can investors value a stock if they don't have the foggiest what the 'e' in p/e will be?" is a common refrain.

Data from Thomson Reuters supports this "confusion hypothesis". Now that most companies have reported their third-quarter results we can see how analysts' expectations for earnings compared with the actual outcome.

While results for all sectors were worse than forecast in January, some industries have been easier to gauge.

The expected third-quarter earnings growth for healthcare of 11 per cent was, under the circumstances, not much different to the 7.3 per cent outcome.

Financials, on the other hand, moved over the same period from expected growth of 46 per cent to minus 106.5 per cent. Strikingly, a decline of "only" 61 per cent for financials was expected as recently as the beginning of October, suggesting analysts have been scrambling to keep up with the fast-deteriorating prospects.

The finger-in-the-air nature of the forecasting is further illustrated by the eerily palindromic nature of the number of financial companies that beat, missed, or matched expectations: 45, 10 and 45 per cent, respectively.

So, an important question for investors is: are we close to a point when even perceptions of earnings clarity may improve?

Sadly not, because so many statements with the third-quarter reports have been laden with bosses bemoaning the murky economic outlook.

Bulls, however, may point to a possible benefit of such gloom-mongering. The longer the uncertainty goes on, the more one would expect shell-shocked analysts to overdo the pessimism.

That could pave the way for some pleasant surprises.