In each region, a mystery shopper visits one of the major grocery retailers for 33 grocery items a mix of own label and core brands. The stores vary but the shopping list remains the same. To allow readers to gauge the price of missing items we calculate their nominal value. We do this in two ways: where items are out of stock, we will calculate the nominal value of those products by calculating the average paid for the items in that chain in the preceding two weeks; if an item is not stocked, we will input a price based on the average paid for that item across all chains in that particular week.
Since its launch in June 1997, The Grocer 33 has provided focus for multiple buyers and store managers at a time of increased pressure in the sector, as well as symbol groups and independent retailers who compete against them, and the manufacturers who supply them.