Annex D: Comparability to Other Government Sources of Rental Data
ONS Index of Private Housing Rental Prices
The ONS Index of Private Housing Rental Prices ( IPHRP)  is a quarterly experimental price index. It tracks the prices paid for renting property from private landlords in Great Britain, including an index at a Scotland level.
Whilst the ONS Index uses same raw data as the Rent Service Scotland ‘Market Evidence Database’, there are some important differences to how the data are processed and used:
- The ONS Index uses the rental data to create a matched-sample dataset to ensure that only like-for-like properties are compared over time.
- The ONS matched-sample dataset retains rental records for a period of time (an assumption based on average tenancy length), and it is therefore an attempt to measure rental price changes for all rents and not just a measure of recent rental market evidence.
- The ONS Index is mix-adjusted in that it uses expenditure weights to adjust to the overall distribution of types of properties in the rental market (by expenditure).
- The Index does not provide any information on actual rental levels, and the Index values provided are not available at a sub-Scotland basis.
Full details of the methodology used to calculate the IPHRP can be found in the June 2013 IPHRP article at http://webarchive.nationalarchives.gov.uk/20160106022839/http://www.ons.gov.uk/ons/rel/hpi/index-of-private-housing-rental-prices/historical-series/iphrp-article.html.
This article can also be supplemented by the January 2015 article ‘Improvements to the measurement of Owner Occupiers’ Housing Costs and Private Housing Rental Prices’ available at http://webarchive.nationalarchives.gov.uk/20160106041638/http://www.ons.gov.uk/ons/guide-method/user-guidance/prices/cpi-and-rpi/index.html.
ONS have also recently produced an article on comparing measures of private rental growth in the UK, available at https://www.ons.gov.uk/economy/inflationandpriceindices/articles/comparingmeasuresofprivaterentalgrowthintheuk/quarter3jultosept2017.
Given the different methodologies used we would not always expect the ONS Index and Private Sector Rent Statistics for Scotland to show the same results. The ONS Index results provide estimates of like-for-like changes over time in rental prices across all private rented households (whether existing tenants or new lets) in Scotland, but do not provide any information on actual rent levels or on trends below the Scotland level. Whereas the Private Sector Rent Statistics for Scotland publication allows an assessment of market-evidence average rents, along with changes over time at a BRMA level and by property size, although some caution is needed in interpreting the results given that the composition and quality of private rental stock can vary by area and can change over time.
Rent Service Scotland 30 th Percentile Rent Figures
Annual information on the 30th percentile of weekly private sector rents by bedroom size is published on the Scottish Government website  , alongside corresponding information on Local Housing Allowance ( LHA) Rates.
There may be a small number of minor differences in the data that was used for previous 30 th percentile calculations compared with the data used for this publication because the Market Evidence Database is a live database and therefore over time there may be some records that are updated to reflect that more up-to-date information becomes available, or where additional statistical quality assurance has been carried out.
The 30 th percentile rents are also presented as weekly rents, rather than the calendar month figures presented in this statistical publication. Monthly rents are seen as a more user friendly way of presenting the data in this publication given that private rents are typically paid in periods of calendar months.
Private Rental Market Statistics for England
The Valuation Office Agency ( VOA) publish Private Rental Market Statistics for England  , which is published twice-yearly. Whilst it presents similar looking statistics to this publication, there are some differences which may affect any comparisons. In particular, rent for 1 bedroom shared properties is presented as gross rather than net of any shared services, and also properties with 5 or more bedrooms are included, not excluded. These differences may impact on any comparisons when looking at average rents for these types of properties.
Private Rental Market Statistics for Wales
The Welsh Government publish annual statistics  on rents paid in the private sector in Wales. The Welsh report includes statistics that look similar to those presented in this publication, however there are some differences in the underlying data which may affect comparisons. In particular, rent for 1 bedroom shared properties is presented as gross rather than net of any shared services.