We do this in collaboration with our sponsors. We always cover the entire store, starting with a coverage across the store of about 100 major categories. What individual categories and segments below that or in additional to these are added depends on what sponsors ask for. Within reasonable limits on penetration and frequency we can measure specific segments in exactly the way you measure your business in other data sources (eg Panel) . You don’t need to measure every smaller category each year, but it’s beneficial to track your biggest categories consistently over time.