Think about the last ten things you bought. Groceries, a new phone, a car service, a flight to Brisbane. In every single one of those transactions, the advertised price was the price. You saw $4.50 for a flat white, you paid $4.50. The tag on a laptop said $1,799 — that's what the bank statement said the next morning.
Now think about buying a home.
You see a guide price of $1,200,000. You spend a weekend imagining your furniture in the living room, you pay for a building inspection, you arrange your finances. Then auction day arrives — and the property sells for $1,380,000. You were $180,000 short. And that's before stamp duty, conveyancing fees, and any number of other costs that don't appear anywhere on the listing — but will appear on your settlement statement. In most Australian states, stamp duty alone on a $1.38M purchase adds another $55,000 or more on top.
The point is this: the gap between what you see on a listing and what you actually pay to own that home is almost always larger than buyers expect, and it has more than one cause. The guide price is one part of the story. The costs that sit invisibly beside it are another. Understanding both is how you go into an auction with a realistic number rather than an optimistic one.
Property may be the only major purchase in most Australians' lives where the advertised price is routinely, significantly lower than what the property will actually sell for - and where substantial additional costs aren't included in the sticker price at all.
This gap between guide and outcome has a well-known name — under-quoting — and while it is regulated to varying degrees across Australian states, it remains one of the most persistent information asymmetries in residential property. Agents set a guide price and buyers are expected to understand that the final sale price could land materially higher. What buyers have rarely had access to is hard data on how much higher, and how consistently, for the specific agent marketing the property they want to buy. That's what we set out to measure.
When we set out to measure agent pricing accuracy, we had to make a choice: what does "accuracy" actually mean? As it turns out, it means two separate things — and confusing them leads to very different pictures of the same agent.
The simplest accuracy measure is the one you'd reach for intuitively: take every property an agent has sold, compare the guide price to the sale price, and find the typical gap. We express this as a percentage of the sale price. An agent whose typical gap is 3% is, on average, pricing very close to the market. An agent at 15% is systematically off by a significant margin.
We call this the median absolute error. "Absolute" means we don't care which direction the error goes — whether the sale came in 4% above the guide or 4% below, both count the same. "Median" means we use the middle value rather than the average, so a handful of wildly mispriced properties don't distort the whole picture. This number answers a single question: how far off is this agent, typically?
In plain English: median absolute error
Imagine lining up all of an agent's recent sales from the one closest to the guide price to the one furthest away. The median absolute error is the gap for the sale sitting exactly in the middle of that line.
An agent with a median absolute error of 3% typically prices within $36,000 of the actual outcome on a $1.2M property. An agent at 15% is typically $180,000 away. Same property price. Very different information.
Here's where it gets more interesting — and where most agent rating systems fall short. Knowing how far an agent is off isn't the whole story. You also need to know which way they tend to be off, and whether that direction is consistent.
We call this the median signed error. When a property sells above its guide price, the signed error is positive. When it sells below, it's negative. By finding the median across all an agent's recent sales, we get their characteristic pricing tendency.
An agent with a median signed error of +15% is a systematic under-quoter: their properties typically sell 15% above their guide. On a $1,200,000 guide, that's an $180,000 gap — every time. That's not random market variation. It's a pattern. And patterns, even uncomfortable ones, are actionable. If you know an agent's guides consistently land 15% below where the market settles, you can plan accordingly.
By contrast, an agent with a signed error near zero but a high absolute error is telling a different story. Their errors aren't consistently in one direction — they're scattered. Sometimes the sale is well above the guide, sometimes below. That unpredictability is harder to navigate, because no simple mental adjustment compensates for noise.
Agent A: The Consistent Under-quoter
Median absolute error: 15% | Median signed error: +15% | Consistency: high
Graded Review - a large and consistent gap. Properties always sell well above the guide. The pattern is predictable but the magnitude matters. Budget well above the guide price every time.
Agent B - The Scattered Guesser Median absolute error: 15% | Median signed error: ~0% | Consistency: low
Also graded Review - the same large absolute error, but no directional pattern. Sometimes high, sometimes low. No mental adjustment helps here. The guide price is essentially uninformative.
Both agents have the same absolute error. But Agent A's pricing, while poor, is at least predictable. Agent B's pricing is noise. This is why we apply a consistency check when assigning grades — a reliably directional agent, even one who consistently under-quotes, gives buyers something to work with. An unpredictable one doesn't.
The median error tells you one thing about an agent's pricing. But the question a buyer really wants answered is more specific: what are the chances this guide price is anywhere near the sale price?
To answer that, we look at what proportion of an agent's recent sales landed within 5%, within 10%, and outside 10% of their guide price. These thresholds matter because they represent meaningful real-world amounts:
We show this as a simple breakdown — for example, if an agent has 10 recent sales:
That picture — five of their last ten properties selling more than 10% away from the guide — tells a buyer something a single percentage number doesn't quite capture. It tells them this agent's guide is, more often than not, a significant underestimate of where the property will land.
Every agent with at least ten eligible sales in the last six months receives an accuracy grade. Grades are absolute - they measure how accurate an agent is, not how they compare to peers in their area.
Knowing that an agent tends to price 10–15% below where properties ultimately sell is helpful context. But what if, instead of asking buyers to do mental arithmetic with incomplete data, we just showed them the realistic range — derived directly from that agent's actual track record?
That's what the Homer Accuracy Adjusted Guide Price Range does.
For every qualifying agent, we look at the full distribution of differences between their guide prices and actual sale prices across their recent eligible sales. We apply the 25th and 75th percentile of that error distribution — the range that captured the middle half of their outcomes — directly to the current guide price:
Homer low = guide × (1 + 25th percentile ÷ 100)
Homer high = guide × (1 + 75th percentile ÷ 100)
This means 50% of the agent's recent sales fell within the Accuracy Adjusted Range relative to their guide price.
When an agent consistently prices below where properties sell, both ends of the range sit above the guide price — that's the range telling you, based on this agent's track record, to expect a higher sale price than the guide suggests. Take an agent whose properties have sold between 10% and 18% above their guide across the middle half of their recent sales. If they're guiding $1,200,000 today, the Accuracy Adjusted Range would show $1,320,000 – $1,416,000.
That's not a valuation, and it's not a prediction. It's what the middle 50% of their recent outcomes looked like, applied to today's guide.
The range is colour-coded based on the agent's accuracy grade — green for Precise or Accurate, amber for Fair, red for Review. The grade and the range work together: one tells you how accurate the agent tends to be in absolute terms, the other tells you in which direction and by how much to adjust.
The range also adapts during a campaign. If the guide hasn't changed, the range uses first-guide accuracy — the most relevant measure of how informative the agent's opening price is. If the guide has been revised, it switches to last-guide accuracy, reflecting how closely their updated pricing tracks outcomes.
The Accuracy Adjusted Range only appears when the data is meaningful enough to act on. The agent must have at least ten eligible sales in the last six months, and the spread between the 25th and 75th percentile must be 10 percentage points or less. A wider spread means the agent's pricing is too variable to produce a useful estimate for any individual property.
A sale is only counted as eligible when it has a recorded sale price, a guide published before the sale, at least 48 hours on the market, occurred in the last six months, and was listed within the last twelve months. Sales that were pre-arranged or where the guide was set after an offer was received are excluded.
When these conditions aren't met, the range isn't shown. The accuracy grade still appears, but the range is withheld rather than displayed with false precision.
No. A valuation model estimates what a property is worth based on its features, location, and comparable sales. The Accuracy Adjusted Range is a calibration of the agent's guide price based on how that agent's guides have historically compared to actual outcomes. The agent has already assessed the property and set a guide - the range tells you how to interpret that guide, given this specific agent's track record.
A valuation asks: what is this property worth?
The Accuracy Adjusted Range asks: given how this agent's guides have compared to sale prices historically, where is today's guide actually pointing?
They answer different questions. Used together, they give buyers a more complete picture than either alone.
If you're currently in the market, here's the practical upshot.
Treat every guide price as a data point, not a destination. In most Australian markets, properties sell above their guide — often significantly. The question is by how much, and whether that pattern is consistent for the agent in front of you.
Factor in what the listing price doesn't include. Stamp duty, conveyancing fees, building and pest inspections, mortgage registration, and lender fees all sit outside the guide price. In most states, stamp duty alone can add 3–5% to your total cost of purchase. Budget for the full acquisition cost, not just the hammer price.
Look at the agent's grade, not just the price. A Precise agent pricing at $1.2M is giving you meaningfully different information than a Review agent at the same guide. The grade tells you how much weight to put on the number.
Where the Accuracy Adjusted Range is shown, use it to anchor your planning. If the range is $1,320,000–$1,416,000 on a $1,200,000 guide, don't walk into the auction with $1,200,000 in borrowing capacity and expect to win. The range is your realistic floor — built not from guesswork, but from the agent's own sales history.
The fact that buyers haven't had easy access to this information before wasn't their failure. The data has always existed — in every sale record, every auction result, every comparison between a guide and an outcome. It just needed to be assembled, analysed, and put in front of buyers before they commit. That's what Homer exists to do.
Homer Agent Awards are updated monthly using rolling six-month sale data. Agents require at least ten eligible sales in the last six months to receive a grade. The Homer Accuracy Adjusted Guide Price Range is displayed when the agent meets the ten-sale minimum and the interquartile range of their signed error distribution is 10% or less. All data sourced from Homer's property transaction database.
