Property Data Websites?

Why is there such a disparity between data found across these types of websites? Which do you think is the more reliable one? I've tended to use SQM research, but for some reason it looks far off from the others.....

As an example, see the pages below, for the same suburb Bundoora:
SQM Research - Weekly Asking Property Prices
http://www.realestate.com.au/invest/house-in-bundoora,+vic+3083
Free Suburb Profile report for Bundoora VIC (3083)
https://www.propertyvalue.com.au/suburb/bundoora-3083-vic

House values range 567, 590, 644, 653K?
House 12 month growth ranges -9.4, -5, 6.3, 7.32%?

 

Anyone have any ideas?

 

they have different collection methods and sample areas. Some stats are collected by suburb and some by postcode. Some are just houses, just units, others are all housing combined. The free stuff is useful but full of holes. Even the paid options aren't perfect but far far better and more reliable in my experience.
For what its worth PDS Pricefinder has Bundoora at 670k and RP Data has it at 644k (lines up with your number as RP is the pro product of "property value" which is also owned by corelogic) and both have 2016 cap growth at 7ish percent.
There is no one magic source in my view - the fact you are looking puts you ahead of most in the pack. Be aware of your generic suburb stats so you understand the trends. Getting in the trenches week in and week out will help you get a feel for what your desired property type in your desired street is selling for. Once you know value you can act accordingly.