Updated summary NIPA methodologies

Survey of Current Business, Oct, 2001

The quantity-extrapolation and direct base-year-valuation methods are similar in that they both use explicit quantity data. In quantity extrapolation, quantity indexes are obtained by using a quantity indicator to extrapolate from the base-year value of 100 in both directions. In direct base-year valuation, quantity indexes are obtained by multiplying the base-year price by actual quantity data for the index period and then expressing the result as an index with the base year equal to 100.

The subcomponents in table 2 are the same as those shown in table 1, but the detail differs to highlight the alternative methodologies used for calculating the real estimates. (12)

Tables 1 and 2 follow.