Cereal and oilseed rape harvest: Methodology

First estimates methodology

First or provision estimates of the cereal and oilseed rape harvest are intended to provide a prediction of the final harvest result. 

First estimates are based on data collected while the harvest is still underway in areas of Scotland. Data are based on initial soundings of harvest results. The collection of yield estimates prior to the completion of the harvest may lead to a level of inaccuracy with these estimates which is difficult to estimate. More information is available under Accuracy and reliability.

Data are collected by Scottish Government and industry bodies to produce these statistics. First estimates of the Scottish cereal and oilseed rape harvest are derived at an annual Crop Report Meeting (CRM). This meeting is typically held in late September. 

A panel of experts from the Scottish cereal industry provide their estimates of harvest yields. Once all the yields have been collated, the industry bodies carry out quality assurance with Scottish Government at the CRM by comparing yield results between different crops and regions within Scotland. This leads to an agreed set of yield estimates which are then combined with final June Agricultural Census area results to derive the first harvest production estimates.

First estimates from growers are collected through different methods and may be estimated from aggregate data, collected through regular reports made to the organisation or collected from growers through electronic, paper based or telephone surveys. Data are collected by area offices of the Scottish Government Rural Payments and Inspections Directorate (RPID), area offices of Scotland’s Rural College (SRUC), agronomists working for commercial bodies, farming co-operatives, and the National Farmers Union Scotland (NFUS) from member farms.

As the moisture content of cereals and oilseed rape can vary from year-to-year and farm-to-farm, depending on the level of rainfall, average yields are adjusted to a standard moisture content of 14.5% for cereals and 9.0% for oilseed rape. This adjustment ensures there is consistency in estimates of the amount of dry matter which can be extracted from cereal grain and oilseeds.

Production estimates are derived by multiplying crop areas (in hectares) by average yields (in tonnes per hectare) at regional level.

Representatives from organisations listed in Table 1 attend the CRM or provide expertise to the process through correspondence. Not all organisations provide yield estimates but all organisations take part in quality assurance.

Table 1: Organisation attendance at Scottish Government Crop Report Meetings, 2020 to 2023

Note 1: Contributed but did not attend.