How Much Is My House Worth - The Evidence Behind the Number and How to Demand It

The gap between the lowest and highest appraisal on the same property is rarely small. Thirty thousand dollars. Fifty thousand. Sometimes more. And all three agents, when asked to explain their number, can point to comparable sales and adjustments that make their conclusion sound defensible. Which it often is.

This is the moment that confuses most vendors. If the comparable sales are publicly available data - the same sales every agent can access - why are the numbers so different? The answer is that appraisal is not calculation. It is interpretation. And interpretation varies.

Why Three Agents Working From the Same Sales Reach Different Conclusions

Every residential property appraisal in Australia begins with comparable sales - recent transactions of similar properties in the same suburb or nearby area. The agent reviews those sales, identifies the ones most relevant to the subject property, and uses them to form a view of what the market would pay.

The problem is that no two properties are identical. A four bedroom house that sold three months ago on the next street is comparable - but it may have a larger block, a newer kitchen, a different aspect, or a better street position than the property being appraised. Each difference requires an adjustment, and adjustments are judgment calls.

One agent looks at that comparable sale and adjusts down by $15,000 for the superior kitchen. Another adjusts down by $25,000. A third decides the kitchen difference is outweighed by the subject the superior aspect of the subject property and adjusts up by $5,000. Three agents, the same comparable sale, three different conclusions - and none of them is necessarily wrong.

Multiply that across five or six comparable sales, each requiring multiple adjustments, and the range of legitimate conclusions widens considerably. By the time three experienced agents have worked through the same data set independently, a $40,000 to $60,000 spread in their conclusions is not a sign that someone is wrong. It is a sign that the interpretation process genuinely produces different outcomes in different hands.

Comparable sales are the evidence. The appraisal is the argument constructed from it. Three agents building three arguments from the same evidence will not always reach the same conclusion - and the fact that they differ does not mean any of them is wrong.

Evidence Strategy or Listing - The Three Appraisal Motivations

The divergence in appraisal numbers is not only about interpretation. It is also about motivation. Not every agent approaching an appraisal is trying to answer the same question.

An evidence-driven appraisal begins with the question: what does the data support? The agent selects comparables based on genuine relevance, adjusts for differences with specific reasoning, and produces a number they can defend sale by sale. That number may not be the most flattering. It is the most reliable.

The second type of appraisal is strategic. The agent has formed a view of the the property value and is presenting a price position that reflects their campaign recommendation rather than a direct read of the comparable sales. A lower list price to attract more buyers. A higher price to test buyer appetite. The strategy can be sound - but the vendor who does not recognise it as a strategy rather than a valuation cannot evaluate it properly.

The third motivation is listing acquisition. Some agents quote high to win the listing. The logic is straightforward: a vendor who receives three appraisals will often instinctively favour the highest because it confirms what they hope their property is worth. The agent who quotes highest wins the listing. After a few weeks on the market with no suitable offers, the agent begins the conversation about price adjustment. The vendor, already committed, adjusts.

The industry term for this practice is buying the listing. It describes an agent who quotes above what the evidence supports in order to secure the agency agreement, intending to manage the vendor toward a price reduction once the campaign is underway. It is the reason the highest appraisal deserves the most scrutiny, not the least.

The Questions That Reveal Whether an Appraisal Is Grounded

The difference between a defensible appraisal and a flattering one is not always visible in the number itself. It is visible in the evidence and reasoning behind it.

The defensible appraisal has a paper trail. Specific sales. Specific adjustments. Specific reasoning. The agent who produced it can walk through each comparable, explain what they weighted and why, and identify the assumptions their number rests on. If any of those assumptions changed, they can tell you how the number would move.

The flattering appraisal relies on atmosphere rather than analysis. The market is moving. Properties like yours are attracting strong interest. Buyers want exactly what you have. The comparable sales are mentioned but not examined. Adjustments are not explained. The number arrives before the evidence has been assembled to support it.

Ask the question directly: which three comparable sales most influenced your appraisal and what adjustments did you make for each one? The answer is the test. An agent who responds with specific sales, specific adjustments, and specific reasoning is working from evidence. An agent who redirects to market conditions or general enthusiasm is not.

The second test is asking each agent what would need to happen for their number to be wrong. An agent who has genuinely interrogated the evidence knows the assumptions their appraisal rests on and can articulate them. An agent who cannot answer that question has not built an appraisal - they have built a pitch.

When Three Numbers Diverge - A Practical Approach

Averaging three conflicting appraisals is a common response and an unreliable one. The middle number is not a more accurate assessment of market value - it is a mathematical compromise between three different interpretations. The accuracy question requires looking at the evidence behind each number, not the position of each number relative to the others.

Go back to the evidence. Ask each agent to provide their comparable sales list in writing. Compare the three lists. Where agents have used the same sales, the difference is in their adjustments - that is where the analytical comparison becomes most informative. Where agents have used different sales, the choice of comparables is itself a signal about each the understanding each agent has of the property and its buyer market.

If two of the three agents used similar comparables and reached similar conclusions, and the third used a different selection and reached a significantly different number, the outlier warrants scrutiny. It may be correct - the third agent may have identified a comparable the others missed. Or it may reflect the listing acquisition motivation.

The cost of overpricing is not visible at the start of a campaign. It accumulates over weeks on market - each week that passes without a sale telling the next buyer that previous buyers passed. By the time the price is adjusted to a defensible level, the negotiating position has been compromised by the time already spent at the wrong price.

The question is not which agent told you what you wanted to hear. The question is which agent can show you the evidence behind the number they gave you.

How Much Is My House Worth - The Questions Worth Asking

Can I trust a real estate agent appraisal?

A well-constructed appraisal based on relevant comparable sales and considered adjustments will typically fall within five to ten percent of the eventual sale price in a stable market. The accuracy depends on the quality of the comparable sales available, the the agent knowledge of local buyer behaviour, and the stability of market conditions at the time of the appraisal. In thin markets with low transaction volumes, or during periods of rapid price movement, the margin of error widens. An appraisal is a professional opinion, not a guaranteed price - and it should be evaluated on the quality of the evidence behind it rather than the confidence with which it is delivered.

Is it normal to get very different appraisals from different agents?

Receiving significantly different appraisals from different agents is common and does not necessarily mean any of them is wrong. Appraisals differ because comparable sales require interpretation - which sales are most relevant, how to adjust for differences between comparable properties and the subject property, and what weight to give to current market conditions. Different agents apply different judgment to the same data and reach different conclusions. The additional factor is motivation - not every appraisal is produced with the same objective, and understanding the difference between an evidence-based appraisal, a strategic recommendation, and a listing acquisition pitch is what allows a vendor to evaluate the numbers they receive.

Does the highest appraisal mean the best agent?

Choosing an agent based on the highest appraisal is one of the most common and costly mistakes vendors make. The highest appraisal is not evidence of the best agent - it may be evidence of the most optimistic interpretation of the data, or it may be a deliberate strategy to win the listing. The relevant question is not which agent quoted the highest number but which agent can produce the most defensible evidence for the number they quoted. An appraisal that cannot be defended with specific comparable sales and specific adjustments is not a market assessment - it is a pitch.

Do I need a formal valuation or is an agent appraisal enough?

A real estate agent appraisal is a professional opinion of likely sale price, provided at no cost as part of the agent selection process. It is not a certified valuation. A formal property valuation is conducted by a licensed valuer, follows a regulated methodology, and produces a report that lenders and legal processes will accept. Certified valuations typically cost between $300 and $800 depending on property type and complexity. For most residential sales, an agent appraisal is the appropriate starting point - a formal valuation is required when a lender needs security assessment, a legal matter requires an independent opinion, or a vendor wants a certified benchmark before proceeding.

Local Market Perspective

Homeowners across the Gawler District and surrounding northern Adelaide suburbs who are preparing to appraise their property will encounter the same appraisal range and motivation spectrum described above - and the same framework for identifying which assessment is grounded in evidence applies here as it does anywhere in the South Australian market.
Gawler residential property agency
provides residential property appraisals and comparable-sales analysis across the Gawler District and northern Adelaide corridor, with appraisals grounded in specific comparable sales and documented adjustments so that vendors can evaluate the evidence behind the number rather than simply accepting it.