Index Number Approaches to Spatial and Temporal Consistency: Comparing the 1985 and 2005 ICP Global Benchmarks

• Activity Number: 550
• Type: Topic Contributed
• Date/Time: Thursday, August 6, 2009 : 8:30 AM to 10:20 AM
• Sponsor: Business and Economic Statistics Section
• Author(s): D.S. Prasada Rao*+ and W. Erwin Diewert and Kim Zieschang
• Companies: University of British Columbia and University of Queensland and International Monetary Fund

Abstract

We note the principal contributors to inconsistency between successive purchasing power parity benchmarks compiled with primary data from global surveys, and updated parities based on national temporal price and volume indexes and an earlier parity benchmark. We assess the degree of deviation for selected countries globally, noting, where possible, the impacts of chaining versus fixed base methodologies in national temporal GDP series, as well as other documented sources of deviation. We assess discrepancies using superlative index number methods and suggest how these methods could be used to reconcile time series and spatial benchmark price and volume indexes. Finally, we consider how national sample designs acquiring the source data for gross domestic product and associated price and volume estimators might be informed by criteria and ancillary information, enhancing their coherence.