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Georgia Valuation Source

Georgia Valuation Source

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Appraisal Basics

How Are Comparable Sales Selected?

The comparable-sales process is the backbone of a credible opinion of value — here's how it actually works.

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Appraisal Basics5 min read

"Comparable sales" get mentioned constantly in appraisal and tax-appeal conversations, but the actual selection process is more disciplined than most people expect. It isn't just picking a few nearby homes that sold recently — it's a structured research and adjustment process designed to isolate what your specific property is actually worth.

What Makes a Sale "Comparable"

A true comparable sale needs to satisfy several criteria at once — not just proximity to your property:

Location

Same neighborhood or a genuinely comparable one — proximity alone isn't enough if market conditions differ meaningfully.

Sale Recency

Sales closer to the effective date of value are generally more reliable, especially in a fast-moving market.

Size & Style

Similar gross living area, bedroom/bathroom count, and architectural style reduce the number of adjustments needed.

Age & Condition

A recently renovated comp and an original-condition subject property require careful adjustment to compare fairly.

Arm's-Length Transaction

Sales between related parties, foreclosures, or distressed sales are scrutinized or excluded unless properly adjusted for.

The Adjustment Process

No two homes are identical, so once comparables are selected, the appraiser adjusts each one's sale price up or down to account for meaningful differences from your property — adding value for features the comp lacks that your property has, and subtracting for features your property lacks that the comp has.

Gross living area (square footage)
Lot size and site characteristics
Overall condition & quality of construction
Age / effective age
Bedroom and bathroom count
Garage / parking
Basement (finished vs. unfinished)
Location influences (view, traffic, proximity to amenities)
Date-of-sale / market conditions adjustment

Why This Matters for a Tax Appeal

A Board of Equalization hearing is fundamentally a comparison of evidence: the county's mass-appraisal basis against whatever you present. A well-documented, properly adjusted comparable-sales analysis gives the board something concrete and verifiable to weigh — far more persuasive than simply asserting a value feels too high. It's also why appraisers can't simply use whichever sales happen to support the lowest number: the analysis has to be independently defensible, or it won't hold up to scrutiny at the hearing.

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Frequently Asked Questions

Most residential appraisals rely on at least three comparable sales, though an appraiser may research and consider more before selecting the most relevant ones. Quality and relevance matter far more than quantity.

You're welcome to share information you think is relevant, but the appraiser must independently research and select the comparables and adjustments used in the analysis to maintain an unbiased opinion of value.

No. Automated models typically apply broad statistical patterns without verifying transaction details or property-specific condition, while an appraiser individually verifies and adjusts each comparable sale.

Net adjustment is the sum of all adjustments in one direction after offsetting increases and decreases. Gross adjustment is the sum of the absolute value of every adjustment, regardless of direction — a high gross adjustment can signal the comparable is less similar overall, even if the net adjustment is small.

Sometimes, if there isn't sufficient recent, relevant data in the immediate area — but the appraiser must explain why it's an appropriate substitute and adjust for any meaningful market differences.

The comparable sales are the actual market evidence behind the opinion of value. Well-selected, well-verified, properly adjusted comparables give a Board of Equalization credible evidence to weigh against the county's mass-appraisal figure.

Not for a market-value appeal — that requires actual sales data, not another property's assessment. However, Georgia law also allows appeals on 'uniformity' grounds, comparing how consistently similar properties are assessed relative to one another; that's a different legal basis than a market-value appraisal.

This information is provided for general educational purposes about the appraisal process and is not legal or tax advice. Comparable selection and adjustment practices follow professional appraisal standards and may vary by assignment — see the Georgia Department of Revenue for property tax appeal specifics.

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