FHRS Audit 2021 Technical report: Sampling

For both the audit and telephone survey of food businesses, sample was obtained from the FSA’s FHRS database.

The initial dataset received from the FSA contained 543,181 food businesses. This sample was processed to exclude food businesses that were ineligible for the research. Specifically, food businesses were excluded if they had not yet been inspected and issued with an FHRS rating, if they operated in a premises that was not publicly accessible and if they were a mobile food business ^{(footnote 1)}.

As there are no contact details available on the FHRS database, it was necessary for IFF Research to undertake telephone lookups. This was achieved by using external data suppliers (Market Location and REaD Group) and through internal desk research.

Once exclusions and telephone lookups had been conducted, 29,364 food businesses remained in the dataset. From this, a starting sample of 12,124 food businesses was drawn and stratified by country, outlet type and FHRS rating to broadly reflect the underlying population of food businesses. Northern Irish and Welsh food businesses and those with an FHRS rating of less than three were oversampled to ensure that robust results could be produced for each group during audit and telephone fieldwork.

Table 2.1 presents the profile of the starting sample of eligible and usable food businesses for audit and telephone fieldwork in terms of country, outlet type and FHRS rating. It should be noted that all businesses sampled for audit fieldwork were included in the starting sample for telephone fieldwork.

Table 2.1 Starting sample for audit and telephone fieldwork

Country

Sector

FHRS rating