8. Data sources and quality
Table of Contents
Table of Contents
Microdata consultation
From March 2025, we aim to introduce grocery scanner data into headline consumer price inflation (CPI) measures. This will affect the publishing of the consumer price inflation item indices and price quotes microdata, in part because quote-level microdata for the groceries market will be discontinued. So that we can consider and best meet user needs when making any changes, we are seeking your feedback to better understand how you have used these microdata.
Please share your feedback by completing this short questionnairewhich is open until Wednesday, 23 October 2024.
Alternative data sources
We are undertaking a programme of transformation across our consumer price statistics, including identifying new sources, improving methods, and developing systems. More information about the project and our ongoing transformation plans can be found in our Research and developments in the transformation of UK consumer price statistics article, released on 1 December 2023. This includes information on the transformation of consumer price statistics on second-hand cars and private rents, which we introduced with the February 2024 index, and our proposed approach to outlier detection in grocery scanner data.
As part of our plans, we updated our transformation overview on 6 August 2024, as well as publishing our updated development plan to outline the rationale for our priorities and their potential impact.
As usual, we welcome your feedback on our work by email to cpi@ons.gov.uk.
Weights for 2024 consumer price inflation statistics
In line with usual practice at the start of each year, the expenditure weights used in compiling the consumer price inflation statistics were updated in March 2024. For the Consumer Prices Index including owner occupiers’ housing costs (CPIH) and the Consumer Prices Index (CPI), they were calculated using national accounts household final consumption expenditure (HHFCE) data for 2022. This is in line with our standard methodology of using data lagged by two years.
It differs from the approach used over the last few years, when there were large changes seen in spending patterns because of the coronavirus (COVID-19) pandemic. Over these years, we adjusted the spending data so that the resulting weights were more reflective of the year immediately before use in consumer price inflation. More information on weights updating is available in our Consumer price inflation, updating weights articles.
The weights for the Retail Prices Index (RPI) were also updated for 2024 in line with the practice followed both before and during the pandemic period, with no additional adjustment to the spending data because of any coronavirus effects.
The weights used to produce the CPI and CPIH have historically been rounded to integers as parts per thousand of the all-items indices. From 2024, we are now using unrounded weights in compiling the indices. The RPI continues to be based on integer weights.
Households and the cost of living
To assist individuals in understanding how the rise in inflation affects their expenditure, we have produced a personal inflation calculator. The calculator allows users to enter the amount they spend across either a reduced or a wide range of categories, to produce an estimate of their personal inflation based on those spending patterns.
Our shopping prices comparison tool shows how the average prices of items have changed over time. As a result, the number of average price series in Table 55 in our Consumer price inflation dataset has been reduced to two, covering petrol and diesel, and Table 54 has been discontinued. The average price data originally presented in these tables are currently still available as time series on our website and can be found using the four-character identifiers in Table 55.
On 28 August 2024, we published our quarterly Household Costs Indices (HCIs) for UK household groups bulletin. The HCIs reflect how different types of households experience changing prices and differ from CPIH and CPI, which are based on recognised economic principles and which provide an aggregate measure of inflation for household spending in the UK.
The HCIs are official statistics in development and this release included new estimates for April to June 2024. It was not possible for this latest release to update the weights for 2024 in line with the standard methodology for consumer prices. This is because of delays in processing the underlying survey data and the need for further ongoing quality assurance. Instead, the most recent estimates have been compiled using the weights for February to December 2023. We will aim to update the weights once the underlying survey data become available.
Consumer price inflation historical estimates, UK, 1950 to 1988
On 18 May 2022, we published our Consumer price inflation, historical estimates, UK, 1950 to 1988 – methodology and Consumer price inflation, historical estimates and recent trends, UK: 1950 to 2022 article. These include new estimates of CPIH and improved estimates of CPI for the period 1950 to 1988. These estimates (published in response to user need for a longer series) are indicative and are for analytical purposes only. They are not intended for official use and do not constitute part of the accredited official statistic series.
Previously, in December 2018, we published our Consumer Prices Index including owner occupiers’ housing costs (CPIH) historical series: 1988 to 2004 article. This series is also not an accredited official statistic, reflecting the historical uncertainty around the backcasts.
Pre-release access
The Bank of England was granted exceptional pre-release access to an estimate of consumer price inflation data at 8:30am on Monday 16 September 2024 so that the data were available for the Monetary Policy Committee meeting held on that day. The letters requesting and agreeing to pre-release are available in the Exchange of letters between the Bank of England and the Office for National Statistics for exceptional pre-release access to the Consumer Prices Index and Labour Market Statistics.
Methodology information
The consumer price indices are normally based on prices collected from outlets around the country, supplemented by information collected centrally over the internet and by phone. The figures in this publication use data collected on or around 13 August 2024.
Our Consumer price indices, a brief guide gives an overview of consumer price statistics, while our Consumer prices indices technical manual covers the concepts and methodologies underpinning the indices in more detail.
Our CPIH Compendium provides a comprehensive source of information on the CPIH, focusing on the approach to measuring owner occupiers’ housing costs.
Our Users and uses of consumer price inflation statistics: July 2018 update includes information on the users and uses of these statistics, and the characteristics of the different measures of inflation in relation to potential use.
Strengths and limitations
We illustrated our approach to Measuring changing prices and costs for consumers and households most recently in December 2023 using three “use cases”, and described how they relate to the measures published and under development.
The three cases refer firstly to the Consumer Prices Index including owner occupiers’ housing costs (CPIH) as our lead measure of inflation based on economic principles. They also refer to the Household Costs Indices (HCIs) as a set of measures that reflect the change in costs and prices experienced by different households, and the Retail Prices Index (RPI) as a legacy measure that is required to meet existing user needs. Our Shortcomings of the RPI as a measure of inflation article describes the issues with the RPI.
Accredited official statistics
These accredited official statistics were independently reviewed by the Office for Statistics Regulation in July 2017. They comply with the standards of trustworthiness, quality and value in the Code of Practice for Statistics and should be labelled “accredited official statistics”.
– How will the introduction of grocery scanner data impact the accuracy of consumer price inflation measures in the UK?
Data Sources and Quality: Ensuring Accurate Consumer Price Inflation Measures
As part of the ongoing transformation of UK consumer price statistics, the Office for National Statistics (ONS) is committed to improving the quality and accuracy of data sources used in calculating consumer price inflation measures. In this article, we will discuss the recent developments in data sources, alternative data sources, weights for 2024 consumer price inflation statistics, and the importance of understanding data quality and limitations.
Microdata Consultation
From March 2025, the ONS aims to introduce grocery scanner data into headline consumer price inflation (CPI) measures. This change will affect the publishing of consumer price inflation item indices and price quotes microdata. To better understand how users have utilized these microdata, the ONS is seeking feedback through a short questionnaire, open until Wednesday, 23 October 2024.
Alternative Data Sources
The ONS is undertaking a program of transformation across its consumer price statistics, including identifying new sources, improving methods, and developing systems. The transformation plan includes information on the transformation of consumer price statistics on second-hand cars and private rents, which were introduced with the February 2024 index, and the proposed approach to outlier detection in grocery scanner data. The ONS welcomes feedback on its work and encourages users to share their thoughts by email to cpi@ons.gov.uk.
Weights for 2024 Consumer Price Inflation Statistics
In line with usual practice, the expenditure weights used in compiling the consumer price inflation statistics were updated in March 2024. For the Consumer Prices Index including owner occupiers’ housing costs (CPIH) and the Consumer Prices Index (CPI), the weights were calculated using national accounts household final consumption expenditure (HHFCE) data for 2022. This approach differs from the one used during the coronavirus (COVID-19) pandemic, when large changes in spending patterns required adjustments to the spending data.
Households and the Cost of Living
To assist individuals in understanding how the rise in inflation affects their expenditure, the ONS has produced a personal inflation calculator. The calculator allows users to enter their spending patterns across various categories, producing
– What are the primary data sources currently used for measuring consumer price inflation in the UK?
Data Sources and Quality: Understanding the Impact on Consumer Price Inflation Measures in the UK
Microdata Consultation: Shaping the Future of Consumer Price Inflation Measures
The Office for National Statistics (ONS) is set to introduce grocery scanner data into headline consumer price inflation (CPI) measures from March 2025. This change will affect the publishing of consumer price inflation item indices and price quotes microdata. To ensure that user needs are met, the ONS is seeking feedback on how users have utilized these microdata through a short questionnaire, open until October 23, 2024.
Alternative Data Sources: Transforming Consumer Price Statistics
The ONS is undertaking a comprehensive transformation of its consumer price statistics, including identifying new sources, improving methods, and developing systems. This includes the introduction of new data sources, such as grocery scanner data, and the development of new methodologies, like outlier detection. The ONS has published an updated transformation overview and development plan, outlining the rationale for priorities and their potential impact. Users are encouraged to provide feedback on these plans to cpi@ons.gov.uk.
Weights for 2024 Consumer Price Inflation Statistics: Updates and Changes
In line with standard methodology, the expenditure weights used in compiling consumer price inflation statistics were updated in March 2024. The weights for the Consumer Prices Index including owner occupiers’ housing costs (CPIH) and the Consumer Prices Index (CPI) were calculated using national accounts household final consumption expenditure (HHFCE) data for 2022. This update marks a return to the
