Our methodology

Where prices come from

Contributors submit receipts, shelf photos and manual observations. Moderators review disputed data. Each price refers to a specific product, pack size, branch and date.

Current prices and period comparisons

The current price is the median of verified regular prices from the last 7 days. Repeated observations by the same contributor at one branch count once. We also display the average, minimum and maximum.

Comparisons use windows of up to 7 days ending today and the selected number of days ago. Daily comparisons use 1-day windows. We require shared branches and at least 3 different contributors in each window. We first calculate each branch median, then the median of those values: every branch has equal weight in both periods. Change = (current median / previous median − 1) × 100%. Missing data is never treated as zero.

Community feedback

Each price has confirmations and disputes. The percentage is the share of confirming votes, not a probability of accuracy. No percentage is shown without votes. The first report enters moderation; three new reports remove the price from publication pending review. A moderator resolves current reports while preserving vote history. Later reports reopen review.

Outliers and promotions

A price is quarantined when it differs from the median by over 35% and falls outside the IQR fences, with tolerance for rounded prices. Moderators review these observations. Sale prices are stored separately; rankings use regular prices.

History and aggregates

History is never overwritten. Background jobs store daily branch aggregates. Charts use approved observations for each Yerevan calendar day. Average, median and range are computed from accepted samples, counting each contributor once per branch. Gaps mean no observations; lines connecting points are not predictions.

GinRadar Food Index

The index is the cost of a fixed product basket with fixed quantities. It is published only when comparable data covers the full basket. Category change is the average percentage change of comparable products. This is a community indicator, not an official inflation statistic.

Personal basket

Personal inflation compares the current products and quantities against the same basket in an earlier period. Store comparisons use a single branch. Incomplete baskets are labelled and never presented as the cheapest complete basket.