The Lake Wobegon Effect?
If analysts were consistently applying their best guess to their earnings forecasts, the consensus average of positive surprises would tend to fluctuate around 50%, not 69%, over the long term. After all, the distribution of forecast errors should be random unless economic or company fundamentals change (and assuming that analysts as a group do not have a crystal ball). But the forecasts are biased, so the frequency of error is too: after the initial burst of optimism, analysts appear to be lowballing estimates whether fundamentals are improving or not—and positive surprises are the result.
To illustrate the irrelevance of upside surprises at the stock level, consider Goldman Sachs’s experience (Display). Over the past 10 years, Goldman Sachs missed quarterly estimates only six (depicted by green diamonds) out of 39 quarters. Even when analysts were trimming their estimates, the company still managed to top them (as depicted by the blue diamonds). In 2008, as the business was deteriorating, Goldman beat Street estimates in two of the four quarters, with the biggest miss coming in the fourth quarter, when earnings fell short of consensus by 106%. By then, the stock had already plunged 64% for the year.