The objective of the present retrospective analysis was to review between- and within-sector variations in an outcome-based measure of animal welfare throughout slaughterhouses that currently supply to Tesco Stores Ltd, UK. Non-conformances in relation to individual scheme standards were designated a specific level in terms of severity and frequency and from this a single outcome status, based on a ‘traffic-light’ system is assigned to the site (which informs both subsequent corrective action and future inspection frequency). Sector-specific, country and time differences were found and underlying contributory factors and associated commercial implications are reviewed.