Guidance

UK HPI development plan for 2018 to 2021

Updated 14 December 2023

The UK House Price Index (UK HPI) working group is responsible for producing and publishing the UK HPI monthly. This working group is made up of HM Land Registry (HMLR), Land and Property Services Northern Ireland (LPSNI), the Office for National Statistics (ONS) and Registers of Scotland (RoS). Part of our role is to make sure the UK HPI meets the needs of its users, explores new and innovative methods to provide the information, and complies with international house price statistics best practice.

The first section of this document focuses on improvements we have already made and areas we want to develop. This forms our development plan over the next 3 years. This plan is not fixed; it will evolve over time reflecting feedback. We will publish an update about the development plan on an annual basis.

The final section provides more detail about how we operate together as a working group. This is to help explain how a working group made of many departments works in practice, and who is responsible for what. If you have a query about the UK HPI, contact us.

1. Improving the UK HPI

1.1 Meeting the user need

To meet the user needs, the group first must understand what the user wants, and needs, from the UK HPI. To do this we have interacted with you (the user) in several ways, through which you have also provided us with feedback. This has been:

• direct contact via email, phone calls, HMLR’s Data Services Team or LinkedIn
• 4 user events which we held in March 2018 to share information and gather feedback from yourselves
• responses to blogs and articles
• feedback from government departments in our regular meetings

All your feedback is collected, logged and then reviewed on a quarterly basis. We then use this to decide which additions and enhancements to the UK HPI we take forward.

1.2 How is the feedback organised

All feedback is welcome. If you contact us via email or phone regarding a query we will usually answer this within 48 hours. However, if your query is more complicated then this may need to be shared with other members of the working group for comment and investigated before a reply is sent. If your request involves an enhancement to the UK HPI, these are categorised into 3 groups, depending on when they can be achieved.

Quick wins – these should be actionable in 6 weeks or under

A recent example of this would be the introduction of ‘next publication date’ mention on the main UK HPI page and headline statistics in each report.

We received this feedback in our March 2018 user events and implemented it in time for the March reports (published in May 2018).

Medium term – these should be actionable in 12 weeks or under

An example of this might be a redrafting of our guidance documentation. Slight changes can be actioned quickly but if larger changes are required this can take longer.

If we think your request is reasonable, it might take up to 12 weeks. If we do not meet this deadline, we will explain to you the reason for the delay and a proposed timeline to providing a full solution.

Major task – these are tasks that will take more than 12 weeks

Fundamental changes to the data or metadata used in the creation of the UK HPI or its publication would require significant technical efforts. Requests of this kind would require further research and detailed investigations into the wider user needs before and change was made. Such a piece of work would also require a business case to release funding.

An example of a major task is feedback received from users during our workshops on additional data they would like to be incorporated into the interactive tool. While most of the UK HPI data is available within the tool, the seasonally adjusted data is currently only available through the data downloads. The interactive tool was developed between HMLR and Epimorphics, an external software supplier. As such any improvements or developments in this area would require further research followed by a business case.

1.3 What you told us about the UK HPI

During early 2018 the UK HPI Working Group held workshops with users in London, Cardiff, Edinburgh and Belfast. We have used the responses from these workshops and combined it with your feedback received through other channels such as our LinkedIn UK HPI group and direct contact to guide our future work programme. Feedback is captured and stored in our customer feedback log which is discussed and prioritised during our quarterly working group meetings.

Feedback was themed and here is a selection.

What you like about the UK HPI includes:

• good user engagement
• evolving methodology
• new interactive tool
• accessible reports
• coverage and granularity of data

What you think we could we do better for the UK HPI includes:

• improvements to reports
• data in interactive tool
• timeliness of publication
• more proactive promotion of UK HPI
• website navigation

1.4 What we are doing in response to your feedback on the UK HPI

The areas in the UK HPI we have improved following the feedback we received, and others we are now working on, include:

Evolving methodology

In December 2017 we implemented improvements to our methodology and we continue to monitor and make sure it meets house price statistics international best practice. Following the development of the UK HPI in 2016 we sought an additional phase of expert peer review of the methods in December 2016 by a senior economist at the International Monetary Fund (IMF). This review confirmed that the UK HPI meets international best practice but proposed some additional enhancements to explore. The suggested enhancements are included in an IMF working paper, How to Better Measure Hedonic Residential Property Price Indexes. Two were raised during the review:

• applying weights at the transaction level
• calculating the UK HPI as a superlative index

Implementation: major task
Both will be explored in parallel during 2018 with a research paper on these findings and their impact planned to be published in early 2019.

Interactive tool

In January 2018 we added new functionality and data to the interactive tool, to help users identify changing house price trends across the UK more easily. These changes were in response to previous feedback received. While most of the UK HPI data is now available within the tool, the seasonally adjusted data is currently available only through the data downloads. The interactive tool was developed between HMLR and Epimorphics; as such any improvements or developments in this area require a business case.

The working group will continue to gather further user feedback throughout 2018. This feedback will be prioritised and discussed with Epimorphics in our annual review meetings with them in May each year.

Implementation: major task
Review meeting with Epimorphics in May 2019 with potential business case.

Reports

In January 2018 we also implemented improvements to the UK HPI reports which included adding links in the reports so that users can download the data table as a csv. Through the March 2018 workshops we received feedback from users on additional content they would like to see within the monthly reports. These include:

• commentary on our seasonally adjusted series
• economic commentary on our country specific reports
• improvements to how existing information is presented such as next publication dates and chart legends

Implementation: quick win
These have all been implemented since our March 2018 release (in May 2018).

Timeliness of publication

The UK HPI is based on transaction data at the end of the conveyance process, calculated based on completed sales. Due to this we will never be as timely as some of the other house price indices, but we are more complete in ultimately capturing the entire market of transacted prices.

Proactive promotion of UK HPI

The UK HPI’s user base is continually growing. To build on the substantial progress made and to promote the UK HPI further we have created a plan to improve this further. Over the next year we will:

• work with journalists to ensure the UK HPI is referenced correctly and challenge any inaccuracies
• introduce several social media campaigns to encourage greater use of the index and highlight the content available on GOV.UK
• promote the UK HPI interactive tool to increase usage
• proactively highlight when user and stakeholder feedback influences enhancements to the index

Implementation: medium term
While we will begin to see the impact of this approach in the medium term, this is a continual process.

Website navigation

There was conflicting feedback in this area. Some users commented that the information is very clear and easy to navigate with reports simple to create, while others felt that the website was too complex and that it takes several steps (clicks) to get to the relevant page. As the UK HPI is published on GOV.UK, there are certain standards which we must adhere to and so changes in this area may not be possible. However, as the publisher, HMLR works closely with GOV.UK and will investigate and report by March 2019 if any changes to GOV.UK standards is being planned that will enable improvements. The Government Digital Service reviews GOV.UK constantly, working in 12-week projects, to tackle aspects of the website. For regular updates read the GDS blog.

Implementation: major task
We will investigate and report by March 2019 if there are any improvements that can be made to the navigation of the website while continuing to meet GOV.UK standards.

During the user events there were a few individual questions which did not directly fit into themes. Some of these don’t directly relate to the UK HPI, but to other HMLR products. We have included them here for completeness and list them as follows: leasehold data, buy to let data and estimation model and volatility.

Leasehold data

HMLR is undertaking a data release programme and one of the releases being looked at is a leasehold dataset. No details of what it may include are available but it will be advertised nearer the release date, which should be before the end of 2018. There is no leasehold information available for Northern Ireland.

Buy to let data

Buy to let properties are not noted in the registration process unless there is a particular type of mortgage reference, which is only an indicator that it may be a buy to let property. As this data is only indicative, no dataset is published. There is no buy to let information available for Northern Ireland.

Estimation model and volatility

Low sales transactions in lower geographies (such as local authorities) can lead to volatility at these levels. Our quality and methodology guidance document has been redrafted to include additional information on our processes. We are also looking to develop measures of accuracy for the UK HPI which may help guide users in this area. These are discussed later in this document.

While not raised directly in our user events or other feedback channels there are some other workstreams which we will be working on. Some of these are areas we have previously communicated to you while others are to ensure we continue to improve the quality of the UK HPI. Each of these are now presented below.

Quality Assurance of Administrative Data

Our Quality Assurance of Administrative Data summarises the quality assurance practices in place for each of the data sources used in the UK HPI. Of the data sources we investigated there were some that need further work to reach the level of assurance we would be satisfied with.

Statisticians in LPSNI have since made a significant effort to engage with staff at HMRC and have increased their understanding of HMRC’s own assurance of this data. In March 2018 we published our quality assurance of sales data from Stamp Duty Land Tax returns reflecting this.

We continue to work on the 2 remaining areas identified, which are:

• ONS is looking to standardise its communication and engagement with the Valuation Office Agency given the potential wider use of the Council Tax Valuation List data across the office
• HMLR continues the work to achieve our application service standards and reduce our processing backlog

Our primary focus will always be the delivery of core land registration services as that is central to our pivotal role in the property and financial markets. In 2018 we will continue to reduce the backlog by:

• redesigning and reshaping how we are organised for operational delivery
• enhancing and expanding our digital services to make the conveyancing process simpler, faster and cheaper

See our Business Strategy 2017 to 2022 for further details.

Implementation: Quality Assurance of Administrative Data documentation was updated in July 2018 to reflect this.

Comparing price indices

When we released the ‘Comparing house price indices in the UK’ guidance article we committed to updating the data sections on an annual basis. Over recent months we have observed a divergence between the UK HPI series and some of the other house price indices which requires further investigation. Once we have completed this analysis we will update this guidance.

Implementation: This guidance document was updated by August 2018.

Additional data to supplement our existing sources

Through ONS the UK HPI Working Group are looking to acquire data on ‘number of habitable rooms’ from the Scottish Assessors which are collected for the purpose of setting Council Tax. While our existing data source (Scottish Energy Performance Certificates) is judged to be of good quality for the use to which it is being put in the UK House Price Index, once the Scottish Assessors data is available an evaluation will be made between both data sources.

Implementation: evaluation during 2018 with a research paper summarising these findings to be published by March 2019.

Developing measures of accuracy for the UK HPI

While the UK HPI is not a sample, as it is ultimately based on all registered transactions, it is still subject to sampling error. This is because we are estimating the predicted price of each property, based on its attributes. However, we only have a selection of attributes to include in the regression model, so the predicted price of each property differs from the actual price. The predicted prices are subject to sampling errors given they are calculated from coefficients (each of which has its own standard error) showing each attribute’s contribution to the price. We will investigate if these can be used to estimate standard errors for the UK HPI.

Implementation: further analysis and refinement during 2019.

2. How the group works together

The team that produces the UK House Price Index is made up of a cross section of 4 contributors based in different administrations within the UK. They are ONS, LPSNI, Ros and HMLR. While each has their own areas of responsibility the group works collaboratively to ensure the different parts of the statistical production process runs smoothly. The following information summarises some of our responsibilities.

2.1 Data collection: price data

Price data is collected by HMLR and RoS. Quality assurance of the data is built into the process. Further detail on these data checks can be found in the Quality Assurance of Administrative Data guidance document.

For Northern Ireland the source of the data is Stamp Duty Land Tax data from HMRC which is processed by LPSNI.

Responsibility for this data is shared between HMLR, RoS and LPSNI.

2.2 Data collection: attribute data

Data from several other sources are provided monthly; these are quality assured and used in production each month. Data sources include Regulated Mortgage Survey data, Valuation Office Agency Council Tax Valuation lists, Scottish Energy Performance Certificates, CACI (Acorn) data and the LPSNI Valuation List.

Further detail on the data checks applied can be found in the Quality Assurance of Administrative Data guidance document.

ONS and LPSNI are responsible for the attribute data.

2.3 Data processing

Price and attribute data are combined to calculate the UK HPI each month. Details of our approach are available in our Quality and methodology documentation. LPSNI does not have the authority to share individual transaction data with ONS, so it is not possible for ONS to produce a UK HPI solely from raw data.

The Northern Ireland component of the UK HPI is calculated by LPSNI. Aggregate data is provided to ONS who combine it with its Great Britain data to calculate the final UK HPI.

ONS and LPSNI are responsible for processing data.

2.4 Monitoring of methods and data

ONS is a member of several European and international housing groups, ensuring the UK HPI is abreast of developments in housing statistics and reflects international best practice.

Monitoring of the UK HPI methodology and its data is the responsibility of both ONS and LPSNI, with LPSNI focused on the Northern Ireland component. These responsibilities include monitoring data feeds and investigating and testing of method improvements. If issues are found, or improvements are required, these will be presented to the wider working group and then escalated to department management boards appropriately. This ensures our processes and methods remain robust, providing assurance for the UK HPI.

ONS and LPSNI are responsible for monitoring of methods and data.

2.5 Publication

HMLR is responsible for the publication of the monthly index. This includes:

• the online reports which include CSV files to the data mentioned
• downloadable data
• the updating of the interactive search tool

HMLR works closely with the Government Digital Service to improve the user experience on GOV.UK.

In addition, on the UK HPI publication day RoS produces a Scotland-focused media release, LPSNI produces a quarterly Northern Ireland focused media release and ONS publishes a high-level summary of the UK HPI on its website. This is done to further promote the UK HPI and direct users towards the main release on GOV.UK.

2.6 Working group communication

All members of the UK HPI Working Group have collective responsibility for discussing, developing and agreeing the methodology, outputs and production processes for the UK HPI. It is noted above that while ONS and LPSNI are responsible for the methodology of the UK HPI, changes to methodology can, for example, have an impact on how the UK HPI is published (which is the responsibility of HMLR) and so wider discussions are required.

Quarterly working group meetings are scheduled to discuss areas such as user feedback, risks and data insight. These discussions are used to plan the UK HPI workplan going forward.

This is a shared responsibility between HMLR, RoS, LPSNI and ONS.

3. Conclusion

This document has been published to give you a greater understanding of the planned development work associated with the UK HPI and provides more detail on how we operate. The work has been prioritised in line with regulatory requirements and known user needs.

We welcome your communication both in terms of this development work plan and more widely in relation to the UK HPI publication and outputs.

We are committed to the continued improvement of the index and aim to introduce more enhancements based on user needs. Thank you for your valuable feedback; if you have anything additional to raise you can contact us through our LinkedIn UK HPI Group.

4. Contact

Eileen Morrison, Data Services Team Leader, HM Land Registry

Email eileen.morrison@landregistry.gov.uk

Telephone 0300 006 5288

Aimee North, Head of Housing Market Indices, Office for National Statistics

Email aimee.north@ons.gov.uk

Telephone 01633 456400

Ciara Cunningham, Statistician for the Northern Ireland HPI

Email ciara.cunningham@finance-ni.gov.uk

Telephone 028 90 336035

Anne MacDonald, Land & Property Data Team, Registers of Scotland

Email Anne.MacDonald@ros.gov.uk

Telephone 0131 378 4991