Data visualizations of Residential Property Price Register

As noted in Monday’s post, the Property Services Regulatory Authority (PSRA) has launched the Residential Property Price Register (RPPR).  It provides sale price for individual properties for all residential sales, including cash sales.  The data includes the address of each property sold, the date of sale, and the price.  AIRO has been examining the data and has produced a set of interactive data visualizations that summarize the entire dataset by local authority and individual property.  These provide average sales price per local authority and also the median sales price to reveal/compensate for the skewing effect of a small number of very expensive properties, prices of individual properties, box plots of sales per local authority, number of new/secondhand properties.

The data visualisations use the full dataset as published.  Whilst we are confident that the vast majority of the data are robust, it is also clear that there are a small number of errors/issues in the dataset that are having a skewing effect.  These are of two types.  First, some properties have the wrong sale prices attached to them (some checking online reveals that the asking price was radically less than the recorded sales price).  We think that a number of them are probably decimal point errors (e.g. the sale price should be recorded €241k not €24.1m).  Second, several properties have been clumped together and not disaggregated (e.g. an entry of 30 apts for €4.5m, rather than 30 entries for €150K each).  We have not cleaned these errors/issues as we do not know what the correct values should be (the use of the median prices compensates for their skewing effect). We did also try and map all of the properties.   This has proved difficult because the PSRA have not used Geodirectory to clean, standardise and geocode their address format, with a variety of formatting used and many spelling mistakes that make matching to Geodirectory not straightforward.  Even for Dublin we only got a 60% address match on a first pass run, meaning the other 40% would require additional work to match.  Despite these issues, the data does give us a good picture of number of sales and sales prices post January 2011 in different parts of the country.

Eoghan McCarthy and Rob Kitchin

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Residential Property Price Register launched

It’s probably no coincidence that the Residential Property Price Register (RPPR) was finally launched yesterday by the Property Services Regulatory Authority (PSRA) just ahead of the latest quarterly reports by Daft.ie and Myhome.ie.  The latter two have been key sources of information about house prices over the past few years, providing asking price information at local authority level, along with the CSO’s Residential Property Price Index that provides average selling price but aggregated to two zones, Dublin and everywhere else.  All three existing sources of property price data have problems, either providing asking rather than selling price, and/or having very weak spatial resolution that enables an analysis at a local level, or in the case of the CSO not including cash sales.

The RPPR addresses these issues in that it provides sale price for individual properties for all residential sales, including cash sales.  The data includes the address of each property sold, the date of sale, and the price.  It is not without its shortcomings, however. Details about the property sold are limited, with no infromation about the size of the property (e.g. number of bedrooms) or site size or if the property is a house or apartment (although it does report if it is new or secondhand).  It only includes property sold since January 2010 meaning that whilst it gives an indication of current values it provides no long-term detail on the drop in value since the start of the crash.  In addition the PRSA notes that ‘In a small number of transactions the price reported does not represent the full market price of the property concerned for a variety of reasons. For example, the price declared may reflect the retention of an interest in the property by the previous owner, or the fact that a part or fraction only of the property is being purchased; alternatively, the property may have been purchased at a reduced price under the Affordable Homes Scheme.’

That said, the RPPR marks a significant step forward in filling a large data gap with respect to residential property in Ireland.  It means that for the first time buyers and sellers will be able to see how the market has been performing locally, rather than having to rely on estate agents guidance.  It also provides property analysts with a much better picture of the state of the housing market.  It therefore is to be very much welcomed.

Rob Kitchin