How Accurate Are Online e-Valuations?

Homes.co.nz releases its own data about how inaccurate its valuations are. But you can probably assume this broadly applies to each of the other websites too.

On average, Homes.co.nz is 9.81% inaccurate (for the 3 months prior to June 2022).

They calculate this by comparing what properties actually sold for, with what their Homes.co.nz estimate was.

This is pretty big.

If your house appears to be worth $1 million on Homes.co.nz, it could actually sell for $98,100 more, or $98,100 less. And that’s only the average.

home valuation

When we dive deeper, we see that only 50.73% of all homes across New Zealand sold within 10% (above or below) of their Homes.co.nz estimate.

Look at it this way: if Homes.co.nz says your property is worth a million dollars you only have a 1 in 2 chance that your home is going to sell within that $900,000 - 1.1 Million band.

The data also shows only 76% of property sales across New Zealand fell within 20% of their Homes.co.nz estimate.

So, in that same scenario you’ve got a 1 in 4 chance that your million dollar property will sell for less than $800K or more than $1.2 million.

However, you should also note that sometimes the online estimation tool is more accurate in some areas, and is less accurate in others.

As you can see from the above map, the website was least accurate in Opotiki District over the last 3 months. On average the Homes.co.nz estimate was out by 27.97%.

But, in Central Otago District, they were out by a margin of 4.97%, on average.

That’s why it’s important that when you use an online tool to value your property, at the bare minimum, you’ve got to do plus or minus 10%.

However, bare in mind that even then you’ve got a 1 in 2 chance that the money you are pocket is outside that band.

Homes vs QV vs OneRoof vs Trademe - Which one is the most accurate?

Ok, so we know that e-Valuations aren’t the most accurate, but of all the websites, which is the most accurate?

To figure this out, we sampled 15 different properties that had sold at auction only a few days before.

That meant that we could know the actual sale price, but that would not have been reflected in official data (so wouldn’t be counted in the websites’ algorithms just yet).

Then we compared the actual sales price to what each of these e-valuation websites thought they would sell for.

What we were looking for was the median error margin.

Said another way: How far off, above or below, were each of these e-valuations compared to the actual auction results?

Here’s how they compared.

How much is my home worth?

As you can see, some were more accurate than others. For instance, on average, TradeMe was 7.3% off and One Roof was 8.3%.

From this sample, QV was the most accurate, followed by Homes.co.nz, TradeMe and then OneRoof.

Now, the conclusion most people will take away from this is that QV is the most accurate at predicting house prices.

Well…you can’t actually say that. Because we’ve only used a small sample, which isn’t statistically significant.

But, what you can take away is this: based on these 15 homes, QV had the least margin of error.

So, for us having done this exercise, if you were to ask us which one we would use– our choice would be QV.

So… What’s the best way to figure out what my home is worth?

All things considered, there are lots of options available for you if you want to get your home valued.

However, you will often find yourself pitting accuracy against cost.

Yes, online valuations are cheap and easy but their own data shows they are quite inaccurate.

From our comparisons, we’ve found QV to be the best. While it’s not statistically significant, that would be our place to go.

At the end of the day, nothing will give you an accurate figure like a registered valuation. It’s just up to you whether you want to spend the money to buy one.

Write your questions or thoughts in the comments section below.

Ed solo

Ed McKnight

Resident Economist, with a GradDipEcon and over five years at Opes Partners, is a trusted contributor to NZ Property Investor, Informed Investor, Stuff, Business Desk, and OneRoof.

Ed, our Resident Economist, is equipped with a GradDipEcon, a GradCertStratMgmt, BMus, and over five years of experience as Opes Partners' economist. His expertise in economics has led him to contribute articles to reputable publications like NZ Property Investor, Informed Investor, OneRoof, Stuff, and Business Desk. You might have also seen him share his insights on television programs such as The Project and Breakfast.

Ok, now for the legal bit:

This article is for your general information. It’s not financial advice. See here for details about our Financial Advice Provider Disclosure. So Opes isn’t telling you what to do with your own money. 

We’ve made every effort to make sure the information is accurate. But we occasionally get the odd fact wrong. Make sure you do your own research or talk to a financial adviser before making any investment decisions.

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