Revisions to previous statistics - revisions policy
(i) Revisions to data are made routinely and are necessary as part of the preparation of the TIFF statistics and Agricultural Accounts (see point ii below). Revisions are usually due to the receipt of additional data which was unavailable at the time of publication. For TIFF, availability of the 2007/08 Farm Accounts Survey data means that previous forecasts of many of the 2007 input costs have been replaced by actual data. The availability of the 2007 December survey of agriculture results replaces previous assumptions, especially in relation to livestock and machinery numbers.
(ii) TIFF uses a wide range of components and data sources and is therefore subject to revisions. All TIFF estimates are treated as provisional until 2 years after their first release. For example, in the latest TIFF publication, 2008 is marked as 'first provisional', 2007 is marked as 'second provisional' and 2006 is considered to be 'final'.
(iii) Additionally, revisions to the TIFF series can also result from improvements and refinements to TIFF methodologies and the correction of any previous errors. Any revisions due to methodological changes or correction of errors are applied consistently across the time series.
(iv) Details of the main revisions in the 2008 TIFF data were supplied in the January 2009 TIFF statistics release. Further information on revisions is always available on request.
April 2009.