CSO publication, , 11am
Since 2020, the number of methods of price collection has increased. As of December 2023, there are now 4 different methods of price collection in the CSO:
Local collection is where prices are collected by approximately 30 CPI price collectors in retail outlets around the country. Approximately 10,000 prices are collected this way.
Online collection is where prices are obtained from online retail outlets by CSO staff in the office.
Centralised collection is used for 135 of the 612 item headings. These prices are collected using post, email, telephone and internet price collection.
Scanner data is where retailers provide the CSO directly with data files for the volume of sales per item in their store over a given reference period.
The collection is undertaken by a specially recruited team of CPI price collectors, with prices collected using Electronic Data Capture (EDC) smartphone devices. In 2016, the EDC system was modernised to take advantage of new technology for mobile data collection. The new system allowed the implementation of new data checks by the price collectors in the field and more efficient transfer of information to CSO.
If a particular product becomes unavailable, then the price collector substitutes an alternative representative product in its place. If a particular retail outlet can no longer be used (e.g. goes out of business), the price collector replaces it with a similar popular retail outlet in the same area. The EDC system is designed to allow the detailed specification of the new product or retail outlet to be recorded. The relevant prices are excluded from the index calculations until two consecutive monthly quotations are again obtained for the substitute product or retail outlet.
The price used is that for a cash transaction. This means that charges for paying by instalments or for use of credit cards, and discounts for paying by direct debit etc., are ignored. Value Added Tax (VAT) and compulsory service charges are included.
Price collectors are required to record if there are any special features associated with the prices recorded. Certain indicator codes are used:
A price should only be recorded if the exact product being priced is on display or in stock at the retail outlet.
This collection is carried out by staff in the CSO offices using online retail platforms of companies trading in the Republic of Ireland. Staff follow the same guidelines as the price collectors would use in store for selecting new products or finding replacements.
Central price collection is typically used where national pricing applies (e.g. health insurance), or where local price collection would not be suitable. There are 135 item headings for which prices are collected centrally through postal, e-mail, telephone enquiries along with internet price collection (see Appendix 4 for full list). All 135 item headings are used in the compilation of the CPI, and 126 item headings are used in the compilation of the HICP (e.g. mortgage interest is excluded from the HICP).
Price data are collected from one central source (e.g. trade associations, Government departments etc.) whenever possible. Where appropriate, prices are collected from a sample of retailers/service providers for the good or service in question. Frequency of inquiry varies across the range of item headings with monthly, quarterly or annual price collection being used as appropriate. In some limited number of cases, price changes will be included as necessary. Typically, this would apply to services where prices are set by a service provider and change at a particular point in time, e.g. electricity.
Scanner data (transaction data) is a new introduction to the CPI that was first used in production of the Consumer Price Index (CPI) in 2020, as a result of a need to find alternative data sources for compiling the CPI during the COVID-19 pandemic. However, the CSO have been working on introducing scanner data into the CPI since 2016.
Scanner data is a rich data source which allows the CSO to use sales data for not only collecting price information on products, but it also allows for the sample of products used from the data to be updated based on the most popular items sold in the shops. This ensures the sample of items used is representative for a large number of items.
As of December 2023, scanner data is used for 2 large retailers and the CSO is exploring the addition of another 2 large retailers in 2024.