Page tree

Versions Compared


  • This line was added.
  • This line was removed.
  • Formatting was changed.


28.13.    Errors in filling customs declarations. International experience has shown that large differences between the highest and lowest prices (unit value range) for single commodity codes are often due to errors in filling out the customs declarations themselves. For instance, declarants may have difficulties in choosing the correct commodity code, filling in the correct partner country or reporting the correct unit of quantity.  To some extent, this can explain the fact that the distributions of unit values are often skewed even at very fine levels of detail (say, the HS eight-digit level).[12] 

28.14.    Simplification of customs declarations requirements. The compilation of unit-value indices presupposes the existence of administrative and regulatory procedures whereby importers and exporters are required to provide enough details on their individual transactions through customs records or other specific surveys (e.g., the Intrastat system). However, as national authorities move towards simplification or even elimination of customs documents, the relevance of administrative records for statistical purposes may diminish in relative terms. 


28.16.    Trade-off between availability and comparability in specifications of price surveys. Although, in principle, it is possible to produce a highly detailed definition of the characteristics of the products to be priced through surveys, in practice, there exists a trade-off between the level of detail in the specifications of items and the ability of survey respondents to consistently match these specifications over time. As in the case of elementary unit-value indices based on data from customs records, survey-based price indices may also suffer to some extent from not comparing like with like, especially if the specifications of the product varieties being priced are too loose, and shifts in the relative share of different price-determining characteristics remain unknown. These difficulties are compounded by the fact that the total number of transactions per respondent per period of time may be relatively small, making it necessary to collect average prices over longer periods of time instead of prices for individual transactions.







 Note that large variance of unit values can imply erroneous declarations as well as heterogeneity in the commodity composition of individual HS codes.