Summary ; Producers of benchmark comparisons are naturally interested in whether the results from one benchmark are consistent with a later benchmark using growth rates between the two to produce a comparison in the later year. Our interest is somewhat different. We recognize that there are differences in price samples, weighting and other factors that will always lead to some differences between extrapolated and new benchmark estimates. In the spirit of some strands of research on the statistical discrepancy in national accounts, we focus on the question of whether there is anything to be learned about the world from examining such differences. The technique we employ looks at several pairs of OECD benchmark comparisons for 1990s, first 1990 - 96 as officially reported and then less intensively at other benchmarks in the 1990s using a common aggregation procedure. The approach is to examine whether there is strong autocorrelation among the residuals of the countries. We then examine some possible influences that might reduce this auto - correlation, including price similarity, distance and a measure of real exchange rates between each pair of countries. The main conclusion of the paper i s that our measure of real exchange rate movements has a strong explanatory effect. While this is a suggestive result it would require more research to establish the nature of any ...