A house down the street may have sold for less than your county assessment and still tell you very little. It may be a different property type, much smaller, newly renovated, or outside the market area that buyers actually use when choosing homes like yours. What makes sales comparable is not simply proximity or a low sale price. It is whether the sale gives a fair, repeatable piece of evidence about the home being assessed.
For Maricopa County homeowners, that distinction matters. A comparison based on a few convenient listings can create more confusion than clarity. A comparison based on recorded sales, clear matching rules, and enough supporting data can show its work.
What Makes Sales Comparable?
Comparable sales, often called comps, are recently sold properties that are similar enough to a subject home that their recorded sale prices provide useful context. Similar does not mean identical. Few neighborhoods have five homes with the same square footage, lot, year built, condition, pool, and floor plan.
Instead, a sound comparison sets boundaries around the characteristics that most directly affect whether two homes belong in the same evidence set. The goal is not to find the lowest nearby sale. It is to avoid comparing unlike properties just because the result looks favorable.
A disciplined review begins with public records, not our opinion. It asks whether the homes share the same broad classification, fall within a reasonable living-area range, sold recently enough to reflect the relevant market, and are located within the same subdivision. It also asks whether there are enough sales to support a conclusion at all.
That last question is easy to overlook. One unusual sale can be interesting. Five consistent, genuinely comparable sales are evidence.
The Four Rules That Keep a Comparison Honest
1. Match the property classification
A detached single-family home should generally be compared with other detached single-family homes. A condominium should be measured against condominiums, and a townhouse against townhouses where public records classify them that way.
This sounds basic, but it prevents a common mistake. Homes with a similar bedroom count or square footage can still belong to different property categories with different buyer demand, ownership structures, maintenance obligations, and market behavior. A patio home and a conventional single-family home may sit near each other, yet not trade in the same way.
Classification is a starting point, not the entire analysis. But without it, the rest of the comparison is built on weak footing.
2. Keep living area within a reasonable range
Living area has a substantial influence on sale price. Comparing a 1,400-square-foot home with a 2,400-square-foot home because both are in the same neighborhood can produce a distorted result, even if both have three bedrooms and similar exterior finishes.
LevyRight uses a living-area range of plus or minus 15 percent. For a 2,000-square-foot home, that means looking at recorded sales roughly between 1,700 and 2,300 square feet. The range is wide enough to find meaningful evidence in many subdivisions, but narrow enough to avoid treating materially different homes as interchangeable.
No single cutoff is perfect in every neighborhood. In a community with only a few sales, widening the size range might produce more results. We could widen the search. We don’t. More sales are not automatically better sales if they require looser matching.
3. Use recent recorded sales
A sale from several years ago may reflect a market that no longer exists. Mortgage rates, inventory, new construction, school boundaries, and buyer preferences can all shift local prices over time. A dated sale can be real and accurately recorded while still being poor evidence for a current assessment comparison.
A 24-month sale window balances two needs: recency and sample size. Limiting sales to the prior 24 months keeps the evidence connected to relatively current market activity while allowing enough transactions for a pattern to emerge in subdivisions where homes do not sell every week.
The recorded sale date matters more than an asking price, a current online estimate, or a listing that never closed. Listings show expectations. Recorded sales show what was reported as having occurred.
4. Stay within the same subdivision
Location is more than a pin on a map. Two homes a half-mile apart can have different school assignments, lot characteristics, construction eras, homeowners association structures, views, street patterns, or reputations among local buyers.
That is why subdivision-level matching is a meaningful discipline. It helps keep the comparison centered on homes exposed to a similar local market. It is especially useful in Maricopa County, where master-planned communities, adjacent subdivisions, and new-build areas can look alike from above while carrying different market signals.
A broader radius may return more sales. It may also blend communities that should not be blended. The convenience of a larger search is a trade-off against relevance.
Why Five Comparable Sales Matter
A single sale can be unusual for reasons public records do not fully explain. A seller may have needed a quick closing. A buyer may have paid more for a specific lot, a remodeled kitchen, or a family connection to the neighborhood. The record shows the transaction, not every circumstance behind it.
Requiring at least five comparable sales reduces the risk that one outlier drives the result. It does not make the comparison infallible, and it does not turn public data into an inspection report. It does create a stronger basis for classifying whether an assessment appears higher, in line, lower, or unsupported by sufficient comparable-sale data.
Sometimes the honest answer is that the data is insufficient. That can happen in smaller subdivisions, communities with few recent transactions, or areas where the available sales fail one or more matching rules. A tool that stretches the geography, accepts larger homes, or reaches farther back in time may be able to produce a number anyway. Producing a number is not the same as producing reliable evidence.
That honesty is the whole point.
Comparable Does Not Mean Identical
Even a carefully selected set of sales has limits. Public records may not capture interior condition, a major renovation, deferred maintenance, solar equipment, premium landscaping, a view, or the practical effect of a busy road. Those details can matter, sometimes a great deal.
This is why a rules-based comparison should be read as a transparent screen rather than a claim that every matched property is worth exactly the same amount. It identifies whether the county assessment is broadly supported by a defined body of local, recorded sales. It cannot see inside every home, and it should not pretend otherwise.
There are also neighborhoods where the rules need patience rather than improvisation. A custom-home subdivision may have homes with highly individual lots. A new community may have limited resale history. A condo development may have few transactions in a given period. In each case, the lack of a clean comparison set is information, not a failure to be hidden.
What a Trustworthy Comparison Should Show
A homeowner should be able to understand why a sale was included and why another nearby sale was not. That means the method should identify the source of the information, use recorded public data, disclose the matching boundaries, and state when the evidence is too thin for a result.
It should also resist the temptation to convert every assessment question into a sales opportunity. The useful answer is not always that an assessment is high. Sometimes the available comparable sales support it. Sometimes they point lower. Sometimes there simply are not five sales that meet the rules.
LevyRight applies these boundaries consistently: matching classification, living area within 15 percent, recorded sales from the prior 24 months, the same subdivision, and a minimum of five comparable sales. The check is free, requires no account, and does not require a homeowner to hand over contact details just to see the result.
A fair comparison is less about finding the most favorable number than about refusing to manufacture one. Start with the public record, keep the rules visible, and let the available evidence speak for itself.
