Abstract
This paper compares Value Line and Institutional Brokers Estimate System (I/B/E/S) analysts' earnings forecasts. Comparing the accuracy of forecasts of a single forecaster (Value Line) to consensus forecasts (I/B/E/S) offers a powerful test of the aggregation principle. Philbrick and Ricks [J. Acc. Res. 29 (1991) 397] conducted a similar study, but found no evidence that aggregation matters. Using more recent data, we reach different conclusions, finding that I/B/E/S earnings forecasts outperform Value Line significantly in terms of accuracy and as proxies for market expectations. I/B/E/S forecasting superiority is largely explained by its timing advantage and the aggregation principle. However, when we build an I/B/E/S consensus using forecasts from the I/B/E/S detail files of individual analyst forecasts, we find that some of its forecasting superiority remains after controlling for these advantages.
