How accurate are Zoopla's 'estmated' house prices?

[WhichMattress]

Hello!

Second question for the day.

Just wondered if anyone has any input on this? I searched Zoopla earlier and examined the "'estimated" property values for a number of properties including my own. In my case, Zoopla stated that it had about "70% confidence" in its estimate and invited me to "refine" it. I added some more details about the property, and at the end of the "refining" Zoopla gave me a very similar estimate - hence I am dubious of the "70% confidence" claim. Does anyone have any insight into how Zoopla comes up with these figures? Most probably they use recent "sold" prices but if the property is in a poor state how do they factor this in?

Cheers!

I think everyone is being overly harsh on what is a generic algorithm never designed to replace an in person evaluation.
It's an good index that should be one data point in a decision - not a number to blindly follow.
Obviously it works better in places where turnover is high and properties are pretty uniform.
As previously mentioned owners / interested parties can adjust the figures by declaring works to increase accuracy / game the system (and I'm not sure if the end user has anyway of knowing if this has been done or not).
I prefer the estimates on houseprices.io - Although I think this algorithm is even more simple, it can't be adjusted so you can mentally do your own adjustments for building work.

Put it this way - they've valued the top flat in our building (of 3 flats) at £50K more than ours. That's despite the fact our flat is 200 feet bigger as it's been extended, has a large garden, a large off road parking space, is in better condition (top flat has been rented out for years) and it's own door.

Don't know whether to feel amused or annoyed!