George Cost-of-Living Report

Headline

Category movers

Coverage & evidence

Methodology

• Source data. Confirmed community observations only: till slips and shelf photos captured by real shoppers, human-verified before they count. Catalogue estimates, pending submissions and observations with assumed dates are excluded.
• Index construction. Chain-linked monthly price level, base = 100 at the first month of verified data. Each month-on-month link is the geometric mean of price relatives over products observed in both months. The geometric mean is used because the arithmetic mean of ratios is upward-biased.
• Publication floors. Minimum cell of 3 verified observations for any published figure; a month below the floor is omitted and the chain bridges the gap. The month-on-month headline is additionally withheld when fewer than 5 products carry the link.
• Privacy. Aggregate only. No raw rows, no identifiable contributor data; contributor counts are hashed-identity counts (POPIA-safe).
• Not the CPI. This is a shelf-price index for a defined grocery basket in one town, not the official consumer price index.