News or Noise? An Analysis of GNP Revisions
This paper studies the nature of the errors in preliminary GNP data,
It first documents that these errors are large. For example, suppose the
prelimimary estimate indicates that real GNP did not change over the
recent quarter; then one can be only 80 percent confident that the final
estimate (annual rate) will be in the range from -2.8 percent to +2.8
percent. The paper also documents that the revisions in GNP data are not
forecastable, This finding implies that the preliminary estimates are the
efficient given available information. Hence, the Bureau of Economic
Analysis appears to follow efficient statistical procedures, in making its
preliminary estimates.
Published Versions
Mankiw, N. Gregory and Matthew D. Shapiro."News or Noise? Analysis of GNP Revisions," Survey of Current Business, Vol. 66, pp. 20-25, May 1986.