Tag: AVM Testing

Best Practices for AVM Testing: Why Sale Prices Matter More Than Appraisal Values

The Challenge of AVM Testing in Quality Control
Automated Valuation Models (AVMs) have become a cornerstone of the appraisal quality control process, with many lenders and Appraisal Management Companies (AMCs) implementing what is commonly known as the “15% rule.” Under this framework, if an appraised value falls within 15% of the AVM estimate, the appraisal undergoes only a cursory review. Conversely, variances exceeding 15% trigger more thorough scrutiny or require review by another appraiser.

While this approach offers operational efficiency, it fundamentally misunderstands the distinction between precision and accuracy. This article examines why using appraisals as benchmarks for AVM testing creates a dangerous circular logic and proposes a more robust methodology centered on actual sale transactions.

Understanding Precision Versus Accuracy
Comparing AVM values to appraised values measures consistency—or precision—not accuracy. This distinction is critical yet often overlooked in the industry. While understanding the consistency between different valuation methods has operational value, particularly for ensuring that credit decisions are based on reliable estimates regardless of methodology, it serves a fundamentally different purpose than accuracy testing.

True accuracy in property valuation refers to how closely an estimate reflects the actual market value at a specific point in time. Market value, regardless of the valuation method employed, is universally defined as the most probable price negotiated between a willing buyer and seller in an arm’s length transaction. Therefore, the only meaningful measure of accuracy is the comparison to the actual negotiated sale price—the endpoint of the price negotiation process.

The Circular Logic Problem
The practice of using appraisals as benchmarks for AVM testing raises a fundamental question: Are we testing whether the model provides an accurate value consistent with actual sale prices, or merely a precise value consistent with appraisal estimates? This distinction has significant implications.

If AVMs tested against appraisals are mistakenly labeled as “accurate” rather than simply “consistent with appraisal estimates,” the quality control process becomes streamlined in a potentially dangerous way. More appraisals pass through without complications or delays from further review, creating a self-reinforcing cycle. This circular process—using AVMs in quality control to validate appraisals while simultaneously using appraisals as benchmarks to test AVMs—is fraught with risk and undermines the integrity of both valuation methods.

The Critical Role of Blind Testing
Determining the accuracy of any valuation estimate requires blind testing—the property’s sale price must be unknown when the estimate is produced. While implementing blind testing for appraisals presents significant challenges due to USPAP standards requiring appraisers to review and consider the terms of sale contracts, AVMs can and should be tested blindly with relative ease.

Most AVM vendors already conduct blind testing routinely as part of their quality assurance programs. This process allows modelers to understand model accuracy before a sale price becomes known—a critical capability for calibrating models and improving their predictive accuracy.

The Importance of MLS Data Suppression
The blind testing process must extend to MLS data, particularly listing prices. While listing prices occasionally match final sale prices, they more typically represent the starting point of buyer-seller negotiations. However, the listing price itself is not arbitrary—considerable analysis has already been completed to determine it.

Real estate professionals conduct thorough studies of the property, neighborhood, and relevant market activity—many of the same activities required for property valuation—before establishing a listing price. When AVMs have access to this information, they gain a significant advantage that may not reflect their true predictive capabilities. Therefore, proper testing must ensure that listing prices remain unknown when estimates are produced, maintaining the integrity of the blind testing process.

MLS data suppression also aligns with real-world use cases. In prominent AVM applications such as mortgage refinancing or home equity loans, the properties serving as collateral are rarely listed on MLS. Most lenders actually prohibit refinancing properties that are currently or recently listed. Testing AVMs without MLS data therefore provides a more realistic assessment of model performance in actual lending scenarios.

Regulatory Guidance and Compliance
The breadth and scope of AVM testing—including methodology selection and resource allocation—must be tailored to each institution’s unique circumstances. Regulatory guidance provides flexibility for organizations to demonstrate compliance within the context of their specific risk assessments.

While no explicit prohibition exists against using appraisal values as benchmarks, the Interagency Appraisal and Evaluation Guidance offers clear direction in Appendix B: “To ensure unbiased test results, an institution should compare the results of an AVM to actual sales data in a specified trade area or market prior to the information being available to the model.” This affirmative statement strongly supports the use of sales transactions as the foundation of AVM testing methodology.

Conclusion: Building a Robust Testing Framework
The distinction between measuring precision and accuracy in AVM testing is not merely academic—it has practical implications for lending decisions, risk management, and regulatory compliance. While comparing AVMs to appraisals may offer insights into consistency between valuation methods, it cannot and should not be mistaken for accuracy testing.

A robust AVM testing methodology must incorporate the following core principles:

• Use actual sale transactions as the primary benchmark for accuracy testing

• Implement truly blind testing protocols that exclude sale prices during estimate generation

• Suppress MLS listing price data for the benchmark property only to ensure unbiased testing. All other MLS-derived information—such as property characteristics, comparable sales, and broader market metrics—should remain fully available and not suppressed.

• Recognize the different purposes served by precision and accuracy measurements

As the regulatory guidance makes clear, institutions have the flexibility to design testing programs that suit their specific needs and risk profiles. However, this flexibility should not obscure the fundamental requirement: AVM testing must measure actual predictive accuracy against real market outcomes, not merely consistency with other valuation estimates. Only through rigorous, unbiased testing against actual sale prices can institutions truly understand and rely upon the accuracy of their automated valuation models.

Setting the Record Straight on AVM Testing Methodologies

Introduction

The Automated Valuation Model (AVM) industry is entering a critical phase—one where regulatory oversight is increasing, use cases are expanding, and performance analysis is under sharper scrutiny. In this environment, testing methodologies must evolve to ensure transparency, fairness, and real-world relevance. A recent whitepaper from Veros Real Estate Solutions, Optimizing AVM Testing Methodologies,” advocates flawed logic that risks reversing progress in predictive model testing and validation.

This op-ed offers an affirmation of the core tenets of what is becoming the industry-standard testing framework: a data-driven testing methodology grounded in sound and prudent validation principles. While Veros challenges this approach, the broader AVM ecosystem—including regulators, lenders, and nearly all major AVM providers—have embraced a process that prioritizes objective, real-world performance measurements over now antiquated methods allowing for data leakage into the Automated Valuation Model.

The Listing Price Issue

The whitepaper in question should be understood as a salvo in the battle over listing prices and their influence on AVMs. Several industry participants have come out with analyses showing that when AVMs incorporate listing price data into their models, they perform much better in tests, but those test results are likely to be a poor reflection of real-world model performance. This is because in most use cases for AVMs, there is no listing price available – think of refinance and HELOC transactions, portfolio risk analyses or marketing (See AV Metrics August 29, 2024 whitepaper[1] or the AEI Housing Center’s Study of AVM Providers[2]).

Specific Issues in Veros’ “Optimizing…”

Below are seven points made in the aforementioned paper that don’t stand up to scrutiny. Let’s break them down one at a time.

  1. Mischaracterization of the Listing Price Concern

Whitepaper Claim: “Knowing the list price doesn’t necessarily equate to knowing the final sale price.” The paper not only puts forward the strawman that others claim that listing prices are equal to sales prices, but it also rather awkwardly asserts that listing prices are not very useful to AVMs

Response: This argument overlooks a key behavioral phenomenon: anchoring. When listing prices are published, they tend to drive sale prices and valuations toward that price[3]. When listing prices become available to AVMs during testing, model outputs shift—often sharply—toward those prices. Look no further than one of the most prominent AVMs on the market, Zillow. They are a very transparent company and publish their accuracy statistics monthly, and when they do, they measure them with and without listing data available, because the accuracy results are strikingly different. As of August 2025, Zillow’s self-reported median error rate is 1.8% when listing prices are available and 7.0% when they are not.[4]

AEI noted this phenomenon in their recent analysis of multiple AVMs from 2024, “Results on the AEI Housing Center’s Evaluation of AVM Providers[5].” AEI referred to it as “springiness” because graphs of price estimates “spring” to the listing price when that data becomes available. The result is inflated performance metrics that don’t reflect true, unassisted, predictive ability. And finally, this issue has been empirically documented in AV Metrics’ internal studies and external publications.

When AVMs are tested with access to listing prices, vendors can tune their models to excel under known test conditions rather than perform reliably across real-world scenarios. This undermines model governance, especially for regulated entities, and conflicts with both OCC and IAEG guidance emphasizing model transparency, durability, and independence.

The solution being adopted as the emerging standard is simple but powerful: only use valuations generated before the listing price becomes known. This ensures unanchored estimates using real-world scenarios where listing prices are unavailable—a more accurate reflection of likely outcomes for use cases such as refinance, home equity, and portfolio surveillance.

  1. Refinance Testing and the Fallacy of Appraisal Benchmarks

Whitepaper Claim: “Appraised values are the best (and often only) choice of benchmarks in this lending space currently as they are the default valuation approach used to make these lending decisions.”

Response: Appraisals are opinion-based and highly variable. In fact, Veros’ own white paper acknowledges that appraisals exhibit high variance, a concession that undermines their validity as testing benchmarks. Appraisal opinions are not standardized enough to provide consistent benchmarks as a measure for AVM accuracy.

Closed sale prices offer a clean, objective benchmark. If the aim is to measure how well an AVM, or other valuation method, predicts market value, then only the actual transaction data meets that standard. AV Metrics published an explanation of the superiority of sales prices over appraised values in May of 2025[6].

Regulatory guidance also emphasizes the superiority of transactions over appraisals for AVM testing. Appendix B of the Interagency Appraisal and Evaluation guidance, December, 2010[7], still the most current guidance of AVM testing, specifically states, “To ensure unbiased test results, an institution should compare the results of an AVM to actual sales data in a specified trade area or market prior to the information being available to the model.”

  1. Mischaracterization of Pre-Listing Valuations as “Outdated”

Whitepaper Claim: The whitepaper asserts that validation results using pre-listing AVM values are artificially low, asserting that these values are outdated and fail to reflect current market conditions. While Veros stops short of using the phrase “outdated and unfair,” that is the unmistakable thrust of their argument: that pre-listing AVM estimates do not reflect real-world usage and disadvantage high-performing models. In the webinar discussion of the whitepaper, Veros repeatedly suggested that “Pre-MLS” testing might use AVM value estimates that were 9 months old.

Response:
This claim is both overstated and analytically misleading.

PTM testing never uses values that are 9 months old, and industry participants know that, because they are familiar with the methodology and AV Metrics’ paper describing it[8]. The reality is that almost all AVM values used in PTM testing were created mere weeks or a month or two prior to the relevant date, which is the contract date. The Veros paper uses confusion over different dates in the process of a real estate transaction to muddy the waters. The timeline below shows how the “median DOM” referred to in the paper and commonly published in business articles is not representative.

Timeline depicting Median Real Estate Transaction Timeline, showing 19 days from listing to contract, and 50 days from listing to close/recording.
The typical transaction takes 50 days from listing to completion, but typically only 19 days from listing to contract. (April 2025)

In the real estate industry, Days on Market (DOM) is often defined as the number of days from Listing Date to Closing/Recording Date. Sources like FRED and Realtor.com report median DOM this way, which for April 2025 was about 50 days.

However, for valuation relevance, the more important measure is the time from Listing Date to Contract/Pending Sale Date—the point when the actual price agreement is made. This is typically much shorter—our April 2025 Zillow data show a median of 19 days nationally.

This matters because AVM predictions made just before the listing date are often only weeks ahead of the market decision point, not months. By contrast, the “closing” date used in some public stats is just a paperwork formality that lags well behind the actual market valuation event.

Furthermore, residential real estate markets do not shift dramatically week to week. The suggestion that valuations generated days or a few weeks prior to the listing date are best characterized as outdated misunderstands the pace of market change and misrepresents the data.

Using pre-listing AVM values does not disadvantage models, nor are those values meaningfully outdated. On the contrary, PTM removes a long-standing bias—early access to listing prices—and holds all AVMs to the same fair standard. The result is a more objective, transparent, and predictive test that rewards modeling performance rather than data timing advantage.

Key Points:

  1. Veros’ “9 months” claim is unrealistic—typical contract timing is closer to 2–4 weeks after listing.
  2. Residential markets move slowly: 1–2% change over several months, often less.
  3. Any slight “age” in pre-listing AVM estimates is minimal, consistent across all models, and far outweighed by the benefit of removing listing price bias.

When tested properly, AVMs show robust performance even when limited to pre-listing data, proving that predictive strength—not access to post-listing artifacts—is the proper basis for fair evaluation.

  1. The Flawed Analogy to Appraisers

Whitepaper Claim (Paraphrased): Veros argues that AVMs should be allowed to use listing data in testing because appraisers do. The whitepaper pleads for AVMs to be allowed to operate like appraisers with access to listing data in order to compete with appraisers on a level playing field.

Response: This argument confuses different points. First, appraisers and AVMs are not equals competing on a level playing field. They are different processes for estimating market value. Appraisers are held to standards to develop and report appraisal estimates by the Uniform Standards of Professional Appraisal Practice. These types of standards are non-existent for AVMs. Perhaps to counter the lack of standards at the manufacturing end of the AVM estimates, model estimates are tested on the backend to evaluate accuracy and meet regulatory expectations.  Appraisers aren’t subjected to the rigorous testing that AVMs go through, though appraisal users typically have review processes in place at both the transactional and portfolio levels.

Second, there are several different “uses of appraisal data” being conflated in this claim. AVMs are able to use many different types of data from listings in their models without objection. They often ingest pictures and text descriptions and they’ve developed very sophisticated AI techniques to tease out information from those descriptions.

But there is one specific issue under debate, and that is the use of the listing price information when AVMs are being tested. Users of AVMs need to understand how accurate a model will be when listing data is not available, as it is not available in most AVM use applications: e.g. refinances, HELOCs, portfolio valuation and risk assessment, etc. For testing to be most applicable to those situations and uses, AVM testing must be done on value estimates not “anchored” to listing prices.

AVMs are evaluated by statistical comparison to a benchmark. Injecting listing prices into the models contaminates the experiment, especially when that price closely tracks the final sale. Appraisers aren’t ranked side by side using controlled benchmarks. That difference is why AVMs should not be tested with access to listing prices, but they certainly should be able to use listing data.

  1. False Equivalency with Assessed Values

Whitepaper Claim: “If we eliminate the use of MLS list prices, should we also argue for excluding other potentially useful data, such as that from a county property tax assessor?” The paper claims that other estimates of value available in the marketplace are not excluded by PTM testing, so it asks why listing prices should be singled out for exclusion.

Response: This argument is a strawman set up to be knocked down easily. Assessed values are stale and generally unrelated to current market value. They also tend to cover every property, meaning that they don’t privilege the small percentage of properties that will be used as benchmarks, thereby invalidating accuracy testing. But, most importantly, they do not create the same anchoring distortion that listing prices do. For these reasons, no one has suggested excluding assessor values, because it wouldn’t make sense. Later in the whitepaper, they answer their own rhetorical question by saying that it is “absurd” to consider eliminating access to assessor data. We wholeheartedly agree. It was, in fact, absurd to even suggest it.

  1. Alternative Proposal: Measure Anchoring

Whitepaper Suggestion: The paper proposes using some statistical techniques to measure the amount that each AVM adjusts in response to listing prices.

Response: This suggestion is interesting for exploratory research, but it is not a viable alternative. It fails to address the basic question: how well does this model predict value when no listing price is available? The Predictive Testing Methodology (PTM) answers that question in a scalable, repeatable, and unbiased way. Simply calculating how much an AVM responds to listing prices does not accomplish that goal.

  1. The Flaws of “Loan Application Testing”

Whitepaper Proposal: Veros suggests a new AVM testing approach based on pulling values at the time of loan application—arguing that this better reflects how AVMs are used in production, especially in purchase and refinance transactions.

Response: While this may sound pragmatic, in practice, “loan application testing” is deeply flawed as a validation methodology. It introduces bias, undermines statistical validity, and fails to meet regulatory expectations for model risk governance. Here’s why:

  • Not Anchoring-Proof
    If an AVM runs after the property is listed (as many do at loan application), it may already have ingested the list price or be influenced by it. This reintroduces anchoring bias—precisely what PTM is designed to eliminate.
  • Biased Sample and Survivorship Distortion
    Loan applications represent a non-random, self-selecting subset of properties. They exclude properties for which there is no loan application (about 1/3 of all sales are for cash and don’t involve a loan) as well as those that are quickly denied, withdrawn, or canceled. This sampling would severely bias testing.
  • Inappropriate Appraisal Benchmarks
    The mix of AVM testing benchmarks would vacillate between appraisals for refinance loan applications and sales for purchase applications. Depending on market conditions, refinance applications can make up 80+% of loan originations, which would mean that the vast majority of AVM testing would be based on appraisals, which are subjective and inappropriate as a benchmark.
  • Non-Standardized Collection & Timing
    There is no consistent, auditable national timestamp for “application date” across lenders. This creates operational inconsistency, poor reproducibility, and potential for cherry-picking.

Veros’ proposal is not a viable alternative to PTM. It lacks the rigor, scalability, and objectivity that predictive testing delivers—and it would fall short of the new federal Quality Control Standards requiring random sampling, conflict-free execution, and protections against data manipulation.

About the Author and the Need for Independent Testing

It is also important to acknowledge that the Veros whitepaper was authored by a model vendor—evaluating methodologies that directly affect its own model’s competitive standing. This is not an independent or objective critique. Veros is an active participant in the AVM space with commercial interests tied to model performance rankings. By contrast, Predictive Testing Methodology (PTM) is conducted by an independent third party, is openly adopted by nearly all major AVM vendors, and has become a trusted standard among lenders seeking impartial performance assessment.

Conclusion: Clarity Over Convenience

At its core, AVM testing is about one thing: accurately establishing an expectation of a model’s ability to predict the most probable sale price of a property. To achieve this, we must rely on objective benchmarks, control for data contamination, and apply consistent standards across models.

The Predictive Testing Methodology (PTM)—already adopted by nearly all major AVM providers—meets these criteria. It has been embraced by lenders and validated through years of use and peer-reviewed research. Anchored in OCC 2011-12 model validation guidance, IAEG principles, and the newly codified 2024 Final Rule on AVM Quality Control Standards, PTM ensures that AVMs are tested as they are used—in real-world, data-constrained conditions. These new federal standards require AVM quality control programs to:

  • Protect against data manipulation, such as anchoring to listing prices;
  • Avoid conflicts of interest, emphasizing the importance of independent testing providers;
  • Conduct random sample testing and reviews, ruling out cherry-picked case studies or selectively favorable data;
  • And comply with fair lending laws, requiring AVM frameworks to be broadly equitable and empirically validated.

Veros’ whitepaper makes the case for less rigorous framework. But flimsy frameworks serve vendors, not users, and especially not regulated users. They inflate performance, mask limitations, and misguide deployment. The industry would do well to resist this regression as such approaches would fall short of the standards now required by law.

The industry should reaffirm our commitment to testing that is transparent, unbiased, and fit for purpose. That is how to build AVM systems worthy of trust and meet both the expectations of regulators and the needs of a fair, stable housing finance system.

AV Metrics is an independent AVM testing firm specializing in performance analytics, regulatory compliance, and model risk management.

[1] https://www.avmetrics.net/2024/08/29/avmmethodologytestingstudy-2/

[2] https://www.aei.org/research-products/report/results-on-the-aei-housing-centers-evaluation-of-avm-providers/

[3] Systemic Risks in Residential Property Valuations Perceptions and Reality. June 2005 from CATC… “Full Appraisal Bias” –Purchase Transactions page 13

[4] See https://www.zillow.com/z/zestimate/

[5] https://www.aei.org/research-products/report/results-on-the-aei-housing-centers-evaluation-of-avm-providers/

[6] https://www.avmetrics.net/2025/05/01/appraisals-are-not-appropriate-for-testing-avms/

[7] https://www.fdic.gov/news/news/financial/2010/fil10082a.pdf

[8] https://www.avmetrics.net/2024/08/29/avmmethodologytestingstudy-2/

Using Appraised Values vs. Arm’s-Length Transactions for Testing AVMs

Testing AVMs is a complex challenge, and when faced with dificult problems, creative solutions often arise. One such solution that has gained attention is using appraised values as benchmarks for AVM testing. The reasoning seems straightforward: both an AVM and an appraisal aim to estimate the market value of a property. So, in cases where a true market value from an arm’s-length transaction isn’t available, appraised values may seem like the next best option.

Appraisals are frequently conducted for refinances, home equity loans, and other non-sales transactions, meaning many properties that don’t transact on the open market still have appraised values available. This availability might seem advantageous, and one might reason that if an AVM—designed to be quicker and cheaper—can match these appraisal estimates, it would be sufficient for testing.

On the surface, this reasoning seems sound: why not test AVMs against appraisals if they’re both providing value estimates? However, this approach is based on flawed assumptions, and the problems with using appraised values as benchmarks for AVM testing begin at the fundamental level.

Appraised Values as Benchmarks

  1. Inconsistency: Appraisals are conducted using structured processes with standardized guidelines, but the significant variability in the types of appraisals (e.g., desktop, drive-by, hybrid, interior inspections) and their purposes (e.g., non-mortgage lending, relocation, litigation, HELOC, refinancing) undermines consistency. This inconsistency makes appraised values less reliable as they may not fully reflect “Market Value,” potentially violating the uniformity required in AVM benchmark testing.
  2. Appraisal Bias Study (quantifiable documented, systemic biases): Evidence shows that appraised values do not exhibit a normal distribution around actual sales prices, suggesting inherent bias*. In particular, appraisers often adjust values upwards to align with expected sales prices to avoid friction with clients. This artificial inflation undermines the accuracy of appraised values as benchmarks, illustrating that they may lead to inaccurate AVM testing.
  3. Appraisal-Derived Data: Appraisal data has inherent limitations due to its sourcing methods, geographic constraints, and the relatively small number of observations. Additionally, it often focuses on specific assignment types and relies on limited-scope appraisals—such as desktop, drive-by, or hybrid data collection—which may not accurately capture the true market value of a property. This variability, coupled with the subjective nature of appraisals, makes them unreliable and impractical for AVM testing. Their limited availability by source and geography and potential for imprecise estimates further reduce their efectiveness as a comprehensive benchmark.
  4. Subjectivity (individual judgment and professional biases): Despite adherence to guidelines, appraisals are subject to the judgment of individual appraisers, introducing bias**. Research supports that appraisals, particularly in certain residential contexts, are performed not to independently assess market value, but to justify predetermined loan amounts. This subjectivity compromises their reliability as benchmarks for AVM testing.
  5. Measuring Error: Using appraised values introduces compounded errors. Testing an AVM against an estimate (appraised values) rather than the true standard (actual market transactions) results in a conflation of two errors—those of the AVM and those inherent in the appraisal. This distorts the AVM’s accuracy, as any bias or error in the appraisal will be reflected in the overall AVM Testing results.
  6. Lag in Market Response: Appraisals are often “rear-looking,” based on historical closed sales, and thus do not capture rapid market fluctuations. This is particularly problematic in volatile markets where real estate prices can change quickly. The lag in appraisals reflecting current market conditions can further distort AVM testing when outdated data is used.

Arm’s-Length Transactions as Benchmarks

  1. Reflects True Market Value: Arm’s-length transactions occur between unrelated, independent parties, ensuring that both buyer and seller act in their best interests. As a result, these transactions accurately reflect the true market value of the property, making them the most reliable benchmarks for AVM testing.
  2. Up-to-Date Information: Arm’s-length sales represent current market conditions, providing real-time data that ensures AVMs are tested against accurate, relevant information. This minimizes the risk of outdated or inaccurate benchmarks, improving the reliability of the test results.
  3. Data Availability: Arm’s-length transactions are abundant, with approximately 4-6 million sales recorded annually across the U.S. This wealth of comparable sales data enables AVM testing in a variety of markets, including less active markets. The breadth of this data makes it a more practical and reliable option for establishing benchmarks.

Conclusion:

The use of appraised values as benchmarks for AVM testing is inherently flawed due to inconsistency, subjectivity, and the lag in reflecting current market trends. These limitations introduce bias, compounded error, and misrepresentation of accuracy in the testing process. This approach can lead to skewed and unreliable results, potentially violating new AVM quality control standards that emphasize the need for market-reflective testing.

In contrast, arm’s-length transactions provide the most reliable benchmarks, as they reflect true market values at the time of sale, accounting for factors like property exposure and typical days on market. To ensure objectivity and compliance with quality standards, AVM testing must prioritize arm’s-length transactions and ensure that the AVMs are blind to the most recent sale and listing prices***. This safeguards the integrity of the results by eliminating any recent influence of pre-existing market values or pricing.

Ultimately, appraised values should be avoided as benchmarks wherever possible, recognizing the inherent methodological limitations and risks to accuracy in testing results. For rigorous AVM validation, the reliance on arm’s-length transactions ensures more reliable, market-aligned outcomes.

 

*Systemic Risks in Residential Property Valuations: Perceptions and Reality, CATC June 2005 Page 13, “Full Appraisal Bias- Purchase Transactions”

**Other research corroborates the notion that certain residential appraisals are performed NOT to establish an independent and objective market value estimate, but to justify a loan amount. (Ferguson, J.T., After-Sale Evaluations: Appraisals or Justifications? Journal of Real Estate Research, 1988, 3, 19-26).

*** Current AVM Testing Methodologies versus our new Predictive Testing Methodology (PTM™) OR How Listing Prices Made Current AVM Testing Obsolete and How to Fix It (AVMNews September 2024)

Introducing PTM™ – Revolutionizing AVM Testing for Accurate Property Valuations

When it comes to residential property valuation, Automated Valuation Models (AVMs) have a lurking problem. AVM testing is broken and has been for some time, which means that we don’t really know how much we can or should rely on AVMs for accurate valuations.

Testing AVMs seems straightforward: take the AVM’s estimate and compare it to an arm’s length market transaction. The approach is theoretically sound and widely agreed upon but unfortunately no longer possible.

Once you see the problem, you cannot unsee it. The issue lies in the fact that most, if not all, AVMs have access to multiple listing data, including property listing prices. Studies have shown that many AVMs anchor their predictions to these listing prices. While this makes them more accurate when they have listing data, it casts serious doubt on their ability to accurately assess property values in the absence of that information.

Three months of data showing estimates by three AVMs for a single property in Austin, TX.
Three AVMs valuing a home before and after it was listed in the MLS from Realtor.com’s RealEstimateSM.

All this opens up the question: what do we want to use AVMs for? If all we want is to get a good estimate of what price a sale will close at, once we know the listing price, then they are great. However, if the idea is to get an objective estimate of the property’s likely market value to refinance a mortgage or to calculate equity or to measure default risk, then they are… well, it’s hard to say. Current testing methodology can’t determine how accurate they are.

But there is promise on the horizon. After five years of meticulous development and collaboration with vendors/models, AVMetrics is proud to unveil our game-changing Predictive Testing Methodology (PTM™), designed specifically to circumvent the problem that is invalidating all current testing. AVMetrics’ new approach will replace the current methods cluttering the landscape and finally provide a realistic view of AVMs’ predictive capabilities.1

At the heart of PTM™ lies our extensive Model Repository Database (MRD™), housing predictions from every participating AVM for every residential property in the United States – an astonishing 100 to 120 million properties per AVM. With monthly refreshes, this database houses more than a billion records per model and thereby offers unparalleled insights into AVM performance over time.

But tracking historical estimates at massive scale wasn’t enough. To address the influence of listing prices on AVM predictions, we’ve integrated a national MLS database into our methodology. By pinpointing the moment when AVMs gained visibility into listing prices, we can assess predictions for sold properties just before this information influenced the models, which is the key to isolating confirmation bias. While the concept may seem straightforward, the execution is anything but. PTM™ navigates a complex web of factors to ensure a level playing field for all models involved, setting a new standard for AVM testing.

So, how do we restore confidence in AVMs? With PTM™, we’re enabling accurate AVM testing, which in turn paves the way for more accurate property valuations. Those, in turn, empower stakeholders to make informed decisions with confidence. Join us in revolutionizing AVM testing and moving into the future of improved property valuation accuracy. Together, we can unlock new possibilities and drive meaningful change in the industry.

1The majority of the commercially available AVMs support this testing methodology, and there is over two solid years of testing that has been conducted for over 25 models.