CSO publication, , 11am
The following validation checks are applied to all prices collected locally.
The most important data check is price change. The price recorded is compared (i.e. validated) with the price for the same product in the same retail outlet in the previous month. Prices outside the relevant price range are re-checked by CPI staff to determine inclusion or exclusion for the purpose of the CPI compilation for that month.
Once the price data is correct and complete, preliminary item indices are calculated using the prices, which passed the data checks, plus those that have been manually accepted. These preliminary item indices are in turn checked to ensure price changes have been correctly reflected in the calculations.
Both micro- and macro-edits are applied, checking price ratios for individual items, elementary aggregates, and higher levels of aggregation.