As the national accounts are compiled within a comprehensive framework, it is possible to reduce the impact of data errors through the confrontation of the various estimates in the national accounts. Data confrontation is built around the conceptual relationships that exist between data items. The best known data confrontation exercise is the compilation of the annual supply and use tables. In the compilation of these tables, estimates of the supply (production) and use (demand) for commodities are compared, with differences in the initial estimates being eliminated. At the same time estimates of the value of production are compared with estimates of incomes attributable to production and differences are eliminated (further details are included in chapter 8 on coherence of the national accounts).
Additional to this data confrontation exercise, each collection area is required to confront its data with other data held by the ABS and other organisations as an important part of the process of ensuring the coherence of ABS statistics. Clearance meetings are held for all the major economic collections used to compile the national accounts as a means of assuring data consistency between those collections and the national accounts, with emphasis on the most recent reference period.
The national accounts quarterly compilation process incorporates a review process designed to highlight inconsistencies and improbable data movements. Problems are identified, investigated and resolved in the process of finalising the GDP estimates. There is a feedback loop to the data collection areas, culminating in the clearance procedures mentioned above.
Over the past two years the ABS has developed quarterly supply and use (QSU) tables as an editing tool to assist in the preparation of the quarterly national accounts. Preliminary quarterly estimates for the production and income components are used as inputs to the model which generates estimates of product supply and use in a time series format. The QSU model enables inconsistencies between the different measures of GDP to be identified and investigated more systemically and at a greater level of detail than is possible by simply examining the aggregate estimates. At the present stage of its development, the QSU model is used as an aid in the compilation of the seasonally adjusted chain volume production and expenditure based estimates of GDP. The model may in the future be extended to incorporate current price estimates, including income based estimates. A description of the QSU model and how it is used is contained in the Research Paper, A Supply and Use model for Editing the Quarterly National Accounts (cat. no. 5258.0).