The BLS is conducting research on whether administrative trade data can be used in place of directly collected data for more homogeneous product areas in the Import and Export Price Indexes (MXPI). These administrative trade data are currently used for MXPI sample selection and contain information that can be used to calculate unit values.
The historical time series of export prices, measured with unit value indexes based on the administrative trade data, are a research product. The data series may be of interest to users researching the potential impact of replacing price indexes with unit value indexes.
This research data product is preliminary and may be associated with larger measurement error compared to the official published indexes. Customers should be aware of the caveats and limitations of this product.
Using administrative trade data to calculate price indexes allows for numerous improvements. The administrative data are collected by other government agencies from importers and exporters and provide a nearly complete record of all international trade shipments. The administrative data contain significantly more observations than are included in the MXPI surveys, potentially allowing more detailed indexes to be published. Using administrative data lowers respondent burden. Finally, the values in the administrative data allow for item weights to be updated more frequently, making a superlative index formula possible. This improvement mitigates substitution biases associated with the Lowe formula currently used in the MXPI.
The primary concern with the indexes calculated from trade transaction records prices is unit value bias. Unit values are an average value of all products within a unit. Unit value bias is mismeasurement of price trends reflecting changes in product mix within a unit instead of price changes for the products in that unit. In the administrative trade data, the research challenge to creating and publishing unit value indexes is to mitigate bias that is introduced when price and price index movements are driven by changes in product mix rather than changes in product prices. To address unit value bias, new methods have been applied to mitigate the bias by identifying homogeneous product areas where unit value bias is less of a concern.
The administrative trade data for exports contain the 10-digit Schedule B number, transaction characteristics, price, and quantity data. Characteristics found in the data are combined to create entry-level items. Monthly weighted unit values are calculated for each entry-level item. These entry-level items are then aggregated to 10-digit Schedule B-based classifications with a superlative, specifically Tornqvist, index formula. The weights used in the Tornqvist formula are an average of the current month's weights and the average of the previous year's weights following the method in Vartia et al. (2021). The current month's price is compared to the average price for the previous year. These entry-level item weight and price data are annually chained to the previous year using the Tornqvist formula. These Schedule B-based indexes are then aggregated to the 5-digit BEA End Use index level using the current MXPI methodology.
Export unit value indexes were calculated for all 136 5-digit BEA End Use product categories. Only those unit value indexes that align with currently published price indexes or that were deemed to have small unit value bias are included in this research data series. Export UVIs are available for 95 of 136 5-digit BEA End Use codes for January 2012 through December 2018. BLS currently publishes data for some of these 5-digit BEA End Use classifications in Table 2. Export price indexes for selected categories of goods and in the MXP Database; for ease of comparison, series IDs are provided for these published indexes.
Publications describing the unit value index methodology are listed here. Note that some methodologies have changed.
Fast, D. and S.E. Fleck. Forthcoming. “Unit Values for Import and Export Price Indexes – A Proof of Concept.” in Big Data for 21st Century Statistics. University of Chicago Press, edited by K.G. Abraham, R.S. Jarmin, B. Moyer & M.D. Shapiro. Available at: https://www.nber.org/books-and-chapters/big-data-twenty-first-century-economic-statistics.
Fast, D. and S.E. Fleck. 2019. “Measuring Export Price Movements with Administrative Trade Data.” Working Paper 518. U.S. Bureau of Labor Statistics. June. Available at: https://www.bls.gov/osmr/research-papers/2019/pdf/ec190080.pdf.
Fast, D., S.E. Fleck and D. Smith. Forthcoming. “Unit Value Indexes for Exports – New Developments Using Administrative Trade Data.” Journal of Official Statistics.
Vartia, Y., A. Suoperä, K. Nieminen and S. Montonen. 2021. “Circular Error in Price Index Numbers Based on Scanner Data.” Available at: https://ssrn.com/abstract=3801530.
For questions pertaining to the unit value indexes or related research, please contact the International Price Program by email or by phone: 202-691-7101.
Last Modified Date: September 24, 2021