Farm Business Survey 2021-22: Farm level emissions and nitrogen usage: Methodology

Coherence and Comparability

This section covers how consistent these statistics are over time and how comparable they are with those of other regions and countries.

Results are considered to be consistent and comparable over time. Results are available from 2019-20 to 2021-22. Methodology has been consistent over this time period.

Trends for most farm types in the Farm Business survey are subject to annual sample variations, as a small number of farms join and leave the survey each year. Farms in the sample may also change their characteristics, and might move from being classified as one main farm type to another. More commentary is available in Scottish farm business income (FBI) - gov.scot (www.gov.scot).

These data complement national level estimates and enterprise specific estimates by providing a view and timeseries of emissions and nitrogen use on real farms. Farms are complex businesses with multiple enterprises that contribute to GHG emissions. For example, cereal farms may have livestock and the scale of this secondary enterprise can vary.

Data do not cover the full agricultural industry and are not comparable with national estimates. Estimates for the whole industry and at Scotland level are available through Scottish Greenhouse Gas Statistics and the Scottish Nitrogen Balance Sheet.

National Scottish estimates use different methodologies that are not directly comparable. Other sources of emissions and nitrogen use data may also use different methodologies. Methodological differences may include:

• different coefficients to estimate emissions and nitrogen content
• including or excluding different contributors and use, for example transport of livestock off farm,
• different methods of accounting for the transfer or life cycle of contributors in the system
• different industry coverage, for example whether all of meat production is included or results are based on a sub-sample
•  different reporting periods, for example, Scottish Greenhouse Gas statistics and the Scottish Nitrogen Balance sheet report calendar year estimates, while our farm level results are based around the financial reporting year

Users interested in comparing results between different statistics and between different countries should evaluate the relevant methodologies of sources used. Different results may be obtained using different methods.