[geolqued]

Those rates are voluntarily self-reported by rental property managers - there's a fairly clear conflict of interest.

According to the following Melbourne has a 5.9% vacancy rate. They use water usage data from the water companies for their analysis. (<50L/day = vacant property)

http://www.earthsharing.org.au/wp-content/uploads/Philip_Soo...

[jacques_chester]

What's the conflict of interest?

[geolqued]

Vacancy rate is basically a property manager's KPI. Additionally, data is collected by the REIV which has no interest in providing bad news about investing in property. https://s.zoomerang.com/s/REIV-January-2013-Vacancy-Survey

REIV vacancy rate is (unleased property on the books) / (property on the books). It's always going to be an under-estimate of true vacancy due to properties that are empty full time and those that are privately managed and temporarily vacant.