How Bashlu compares supermarket prices: methodology

Source

Under the Price Transparency Law (2014), every large chain publishes the price of every product at every branch, every day. Bashlu reads these files each night. Every price on the site carries the date it is from; a chain whose prices are more than 48 hours old is marked.

Branches

Branches of one chain mostly charge the same price. Bashlu uses the price most of a chain’s branches charge; a branch that differs keeps its own price for the app, but the index uses the common one.

Choosing the product

Each item is the plain, everyday product, with no organic or premium varieties, and the cheapest suitable one at each chain. A person checks every match between an item and a product on the shelf, so that two chains are compared on the same thing.

Share of the pack

Exactly the stated amount is counted: 200 g of a 1 kg bag is a fifth of its price. Only pack sizes a household buys are used, so a 25 kg sack does not make a chain look cheap.

Promotions

Promotions and loyalty-club prices are not included: they change weekly and depend on the shopper. The index compares regular shelf prices.

Gaps and outliers

A price far from the other chains’ median is marked “under review” until a person checks it. From November 2026, when a chain has no checked price for an item, the median of the other chains stands in and the cell is marked ≈, so the basket is always complete and the reader sees where. Months before that compared only the items every chain had.

Corrections

A month is recorded once, on the 1st, and not recalculated. If a mistake is found, the month is re-recorded, marked with the date of the correction, and the page says what was corrected. Found a mistake? Write to [email protected].

Limits

• It is one basket, not everything you buy.
• Promotions and loyalty-club prices are not included.
• It is the price most of a chain’s branches charge; your branch may differ.