Methodology

Data sources and hierarchy

We rank sources in three levels. Primary sources (Texas statutes, the Texas Comptroller of Public Accounts, official appraisal district publications) always govern. Authoritative professional sources are used only where primary sources do not cover a subject. Secondary sources are used only for context and never override a government source.

Source traceability

Every important factual claim on this site is tied to a registered source record that stores the publisher, URL, jurisdiction, verification date, and what the source supports. Source sections appear at the bottom of content pages. Deadlines additionally record the tax year and rule they apply to. If a claim cannot be verified, we omit it or label it as not yet verified.

Comparable-property methodology

We do not call two properties "comparable" merely because they are nearby. Texas Tax Code § 23.013(d) identifies the factors that determine comparability: location, square footage of lot and improvements, property age, property condition, property access, amenities, views, income, operating expenses, occupancy, and easements or restrictions. Section 23.013(b-1) sets sale-recency windows: for residential property in a county with more than 150,000 people, a comparable sale must have occurred within 36 months of the valuation date (24 months otherwise), subject to a narrower exception.

When verified comparable data is available, our tool shows each candidate with its characteristics, its source, and the similarity factors it matches. When verified data is insufficient, the tool says so rather than producing a misleading comparison.

Calculations

Every calculation the site performs shows its inputs, assumptions, formula, output, source, and limitations. Estimates are labeled as estimates, user-provided values are labeled as user-provided, and official values are labeled with their source. We do not display false precision: if the data only supports an approximate range, we present a range.

Limitations

This site is an informational research layer. It cannot determine the legally correct value of a property, cannot interpret contested legal standards, and cannot predict how an Appraisal Review Board will rule. Its comparisons are informational only.

Update process

Pages and data records carry a last-verified date and review status. We re-verify deadline-sensitive content before each protest season. Pages whose underlying facts have not been re-checked are flagged internally and are not presented as current.

Some figures are different from the rest, and we treat them differently. A rule changes only when a legislature changes it, but a handful of figures are republished by the government on a calendar, which means a page can stay consistent with itself while quietly going out of date. Three on this site work that way: Nevada’s published installment dates, which expire with the fiscal year; the maximum rents that qualify a Nevada rental for the 3% abatement, which are federal fair market rents renewed annually; and Oregon’s exception-event dollar thresholds, which are indexed to the CPI — their accuracy decays by design, because the law has not changed but the number has.

Each of those figures is listed in an internal review schedule with the interval a verification can stand, the source that republishes it and the place it is used. When an interval elapses, that check fails and the figure is re-read before anything else ships. Where we could have published a number but chose not to, the same schedule records why: for Florida’s Save Our Homes limit we point you at your own TRIM notice rather than print a CPI figure that is superseded every January.

How errors are corrected

See our corrections policy. In short: we verify reports against primary sources, correct confirmed errors, and record what changed.