Research and developments in the transformation of UK consumer price statistics: January 2026

There are several articles included in this iteration of our research series. These articles include:

• Impact analysis on transformation of UK consumer price statistics

• How multilateral index methods help us understand grocery scanner data

• Overview of how we use scanner data in consumer price inflation statistics

• Changes to the provision of microdata outputs for consumer price inflation statistics

This is the ninth article in our transformation of consumer price statistics series. This series will update users on our research to modernise the measurement of consumer price inflation in the UK, while maintaining the quality and integrity of our outputs.

Impact analysis series

We have updated our impact analysis series to show the indicative impact of new groceries data and methods on headline consumer price statistics. We outline the impact of including new data and methods on groceries in Consumer Prices Indices including owner occupiers' housing costs (CPIH), the Consumer Prices Index (CPI), and the Retail Price Index (RPI) in our Impact analysis on transformation of UK consumer price statistics: January 2026 article.

Methods research

Alongside our impact analysis article, we have also published three methodology articles.

We summarise the index methods we will be using with grocery scanner data in our How multilateral index methods help us understand grocery scanner data methodology. We also provide an empirical analysis, comparing these methods to some more traditional index methods (which are often understood as "basket indices").

We summarise a variety of topics relevant to the introduction of grocery scanner data in our Overview of how we use scanner data in consumer price inflation statistics article. These explain how grocery scanner data methods fit into the CPI basket, and the treatment of quality change, discounting and refunds.

We describe the changes we are making in March 2026 to the supplementary datasets we publish alongside our core price statistics datasets in our Changes to the provision of microdata outputs for consumer price inflation statistics article. We explain changes to widen the scope of our shopping prices comparison tool, the updates to our average prices dataset to also cover scanner data, and the introduction of a new regional analysis dataset.

The next improvement we intend to make is introducing grocery scanner data in February 2026 (published in March 2026). We will introduce scanner data for 50% of the groceries market, with the remainder still covered through the existing local collection.

We will continue to work with our Advisory Panels on Consumer Price Statistics (APCP) and broader users during this period of research. We welcome feedback on any of the research completed to date, which may help shape the ongoing transformation of consumer price statistics to include new data and methods. To share your feedback with us, please email cpi@ons.gov.uk.