Below explains the differences between the two sources of rental data: what they refer to, and how they should be interpreted.
Ministry of Business, Innovation and Employment (MBIE) and Trade Me data
MBIE publishes rental price data which is used to calculate market rent. Its data is also used for regional housing reports and other analytical publications.
The website Trade Me Property (“Trade Me”) produces median rent statistics.
The two data sources measure different things
Both series of rental data are valid, but they measure different things. Neither of these series measures rent paid by all tenants. Rather, they only capture the weekly rent for new rentals on the market.
Tenancy bond data
Tenancy bond data measures the average rent of actual bonds lodged by private landlords with MBIE. This series presents a measure of the actual price of newly acquired rentals. Under the Residential Tenancies Act (RTA), every landlord that receives a bond is required to lodge it with MBIE, unless it’s a tenancy specifically excluded under the RTA (e.g. holiday homes). There is no distinction between furnished and unfurnished properties in bond data which can influence the price of rentals.
Trade Me listing data
Trade Me publishes the median asking price of rentals as advertised on Trade Me Property. This is a record of the price of rentals listed on New Zealand’s biggest property website. Their Rental Price Index presents a picture of price changes of advertised rentals for people who rely on publically advertised rentals. Trade Me’s data refers to properties ‘asking’ price rather than the agreed price, meaning Trade Me data includes rentals with asking rents that have not yet been rented out.
Tenancy bond data is publically available in these places
Rental bond open data
MBIE provides monthly data on the number of bonds lodged, active bonds, mean bonds, geometric mean, synthetic upper and lower quartile rents for New Zealand as well as a Territorial Authority level.
The difference in average rent between the two sources
Median rent from new bonds lodged and the annual change resulting from it is typically lower than Trade Me data as noted in the tables below:
|Published 'Median Weekly Rent' June 2017|
|Area||Median Rent from Trade Me Listings1||Geometric Mean2 Rent from Bonds||Average Rent from Bonds|
|Published Annual Change from June 2016 compared to June 2015|
|Region||Median Rent from Trade Me Listings1||Geometric Mean2 Rent from Bonds||Average Rent from Bonds|
2. MBIE: Open Data(external link)
Because the median value for rents from bonds tend to fluctuate around clusters of $50, interpreting changes in median rentals can be difficult with bond data. The ‘geometric mean’ is calculated by multiplying rents together and raising the result to the power of 1/x where x is the number of rents. Internal research conducted by MBIE suggests that this measure closely tracks median rents and therefore is the best comparison with Trade Me published medians.
In October 2014, median rent from Trade Me listings typically sits in between geometric mean (median) rent and average rent from bonds lodged. Between the regions the percentage changes can vary between the two sources with Trade Me listings showing a lower percentage change in Auckland while Wellington and Christchurch has significantly higher annual changes than bond data.