Total Income from Farming Estimates: Methodology
This report provides information on the methodology of total income from farming (TIFF) estimates. Information is included about methodology, estimation methods and limitations.
Accuracy and Reliability
This section discusses how accurately and reliably these statistics portray reality.
There is no simple way of measuring accuracy of Total Income from Farming because it is compiled from multiple data sources and methods.
Data quality
The quality of information collected towards TIFF estimates can vary depending upon the data source and availability of data.
Many sources of data used in estimating TIFF are of very good quality, including the June Agricultural Census, Farm Business Survey, Cereal Production and Disposal Survey, and surveys with extremely high or total population coverage including surveys of slaughter and milk production.
The potential for data processing errors is regarded as low risk. This is due to the extensive use of cross-checking validation routines used by Scottish Government and industry bodies who provide published industry data. If necessary, data suppliers are contacted to validate data.
Results are examined alongside previous outputs and related evidence from alternative sources in order to ensure that the data and methods being used are reliable and to assess trends or switches in areas, volumes or prices that look unreasonable.
Accuracy and reliability of initial estimates
Data for the most recent year are initial estimates, and revisions are made to second and later estimates as more accurate data become available. Revisions are made in line with the regular revision process for TIFF.
This means that second and final releases of data provide more accurate figures. A trade-off is made between accuracy and timeliness in releasing an initial estimate of TIFF. More accurate estimates of TIFF can only be made by delaying publication until the final information is received.
The impact of revisions on the accuracy and reliability of TIFF estimates is detailed under Effects of recent revisions.
Initial estimates are based heavily on proxy estimates and projections, particularly for estimates of costs. Colour coding and notes are included in the main tabular data release supporting the TIFF publication to indicate the reliability of components contributing to the TIFF estimates.
Sampling error and bias
Some TIFF estimates rely on sample survey results. As surveys do not cover the entire population, results are susceptible to sampling error.
Results of the June Agricultural Census, the Farm Business Survey and the Cereal Production and Disposals Survey are considered to be high quality. More information about the methodology and accuracy and reliability of these products is available in their methodology information:
Scottish Agricultural Census: results - gov.scot