24.65 The timeliness of statistical information refers to the delay between the reference period to which the information pertains, and the date on which the information is made available. The timeliness of information also influences its relevance; users obviously want data that are as contemporary as possible.
24.66 The source data used to compile the national accounts are available with varying degrees of timeliness, frequency, accuracy and detail. Successive vintages of source data are likely to be more accurate. This is consistent with the nature of business accounting systems where sub-annual data from management information systems are updated and eventually replaced by audited annual accounts.
24.67 The ABS aims to collect the various vintages of source data as soon as satisfactory results are typically available from the respondents' own systems. These may not be final data, and, in some cases, businesses may not be able to respond in accordance with the set deadlines at all, resulting in an expected level of non-response. Survey systems are designed to impute values for late or non-responders. A consequence is that initial estimates are likely to be revised.
24.68 There is an important trade-off between the accuracy and reliability of the estimates and the timeliness of their release. To meet the decision-making needs of users, the Bureau is pressured to produce statistics in as timely a fashion, and as frequently as possible. Complete or accurate data may not be available with the desired timing or can only be obtained at unacceptably high resource costs if at all, thereby compromising data accuracy. Both accuracy and timeliness are characteristics of quality – the ABS relies on feedback from users as to the optimal balance between them.
24.69 The trade-off between timeliness, accuracy and detail is accommodated by way of the sequencing of releases of national accounts publications. The first published quarterly estimates are usually made available about 60–70 days after the reference period. The detailed annual estimates are released between four and five months after the reference period. The most detailed national accounts estimates relating to production, income and expenditure are contained in the input-output tables, which typically become available about 38 months after the reference period. The quarterly financial accounts are usually released in the month following the corresponding quarterly national accounts, and the annual state accounts are released in the month following the annual national accounts. Australia's national accounts rate well against those of other countries in terms of their timeliness – particularly when the level of detail made available is taken into consideration.
24.70 A number of countries, particularly those that release national accounts estimates early, release a preliminary issue of the quarterly national accounts, followed later by 'final' estimates. The preliminary releases are often based on a partial view of the economy and require a certain amount of forecasting. For example, it is possible to base a preliminary estimate of quarterly production-based GDP (or GDP(P)) on two-months data if monthly production indexes are available, and to then forecast the third month. This method obviously improves the timeliness of the national accounts as they can be released soon after the end of the quarter, although the preliminary releases are normally issued with caveats. The ABS has not chosen this approach, and monthly production indexes are not compiled to enable the use of this approach.