HPI and house price statistics comparison

This guidance highlights the differences between the Scotland figures within the UK House Price Index (HPI) and our house price statistics.

For more information about how we compile our statistics, see our guidance notes.

Summary

The headings below provide an overview of the differences between the methodology and content of the HPI and the methodology and content of the quarterly statistics.

Frequency of publication

House Price Index: Monthly

RoS house price statistics: Monthly, quarterly and annually, plus an annual 10-year report

Base data source

House Price Index: Applications for registration in the land register, plus house types derived using RoS methodology and base mapping data (Ordnance Survey ©Addressmap)

RoS house price statistics: Based on applications received for registration in the land register within each quarter

Date range of extraction

House Price Index: Based on the date of entry to the property for each calendar month

RoS house price statistics: Based on applications received for registration in the land register within each quarter

Price range

House Price Index: All data with a consideration

RoS house price statistics: £20,000 to £1 million

Average house prices

House Price Index: Based on geometric mean – sub-Scotland local authority figures will be based on three-monthly moving averages to reduce volatility

RoS house price statistics: Based on arithmetic mean and median

Case mix adjustment

House Price Index: Yes – based on room numbers provided via EPC data

RoS house price statistics: No

Seasonal adjustment

House Price Index: A separate seasonally adjusted series is available, calculated at the regional and national level only

RoS house price statistics: No

Revisions

House Price Index: Three-month cycle – final figures at three-month update

RoS house price statistics: Updated on a quarterly basis up until one year after the first publication

Volume of sales

House Price Index: Yes

RoS house price statistics: yes

Property types

House Price Index: Yes – detached, semi-detached, terrace, flat

RoS house price statistics: Yes – detached, semi-detached, terrace, flat

Cash sales

House Price Index: Yes

RoS house price statistics: Cash sales are included but not separately identified

New builds

House Price Index: Yes

RoS house price statistics: New builds are included but not separately identified

Buyer analysis

House Price Index: Yes – statistics relating to first-time buyers and former owner-occupiers is extracted from CML data

RoS house price statistics: First-time buyers and former owner-occupiers are included but not separately identified

Results

House Price Index: Average prices presented as geometric means are typically closer to the median than the arithmetic mean

RoS house price statistics: Typically the use of an arithmetic average will lead to a higher price than the use of other measures. This is because an arithmetic approach to calculating the average price takes full account of the extreme value properties that have been sold. As a result, the average price can be sensitive to high-value property

Average prices

The average price trends when comparing the HPI with our house price statistics are very similar. There's a slight delay to changes in our figures, because our data is based on the date of registration, while the HPI is based on the date of entry. Registration can occur up to several weeks after the date of entry.

Quarterly and monthly averages are higher in the RoS statistics than in the HPI. This is expected because of the different methodologies used - specifically, the use of an arithmetic mean within the RoS statistics, versus a gemoetric mean in the HPI. The geometric mean will typically be closer to the median than the arithmetic mean.

The HPI monthly figures are smoother than the RoS monthly house price statistics, again because of the different methodologies used. The HPI figures are mix adjusted, while the roS house price statistics use the mean of all sales between £20,000 and £1 million. This means the RoS figures are more prone to fluctuations in the market, for example if a high number of high or low-value sales are registered within a particular month.

On average, the HPI house price averages are 15.5% lower than RoS monthly house price averages. The difference ranges from 5.2% to 28.4% lower than RoS stats.

Volumes

Again, the volume trends when comparing the HPI with RoS house price statistics are very similar. There are slight differences in the volumes being presented because the RoS data is based on date of registration, while the HPI is based on date of entry. Overall, across the period shown, the difference between the volume figures was less than 1%.


Was this page helpful?