Methodology · Named for Tax Code §42.26 · Equal & Uniform
How the screen works, and what it measured.
For TDLR-registered property tax consultants. We sell data and software; we do not represent owners. Every number on this page is computed from public appraisal-roll files and HCAD's published hearing outcomes, and is reproducible from the cited sources. Prefer the two-page PDF? Download it →
The test — Tax Code §41.43(b)(3) / §42.26(a)(3)
A property is unequally appraised when its value exceeds the median appraised value of a reasonable number of comparable properties, appropriately adjusted. The screen applies that statutory test, literally, to every commercial parcel on the certified roll.
Comparables come from the same roll with the same improvement-type code and the same TCAD market area, building size within ±50%, year built within ±15 years, land share within ±0.25 of the subject. Parcels that are mostly land (land share > 60%) are excluded from both sides — land plays need a land screen. Each comparable's improvement value per square foot is adjusted for size and age, and the subject is compared with the median of the adjusted comps.
Larger buildings trade at a lower $/sf; newer buildings at a higher one. Both parameters were selected by grid calibration against two full years of published ARB outcomes and are stated on the face of every evidence exhibit.
When a parcel is flagged
Excess over the median ≥ 10% (a business filter — the statute itself has no threshold) in a cohort of ≥ 5 comparables with dispersion (IQR ÷ median) ≤ 0.60. HIGH confidence: ≥ 8 comps, dispersion ≤ 0.25. MEDIUM: ≥ 5 and ≤ 0.40. Only evidence-grade cohorts — same type and same market area — receive evidence exhibits; low-confidence flags showed no measured lift and are labeled and excluded.
Savings are cap-aware
Estimated savings = the reduction that actually reaches this year's taxable value, at the parcel's own composite rate (summed over its taxing entities). A market reduction below the taxable value doesn't save money this year but lowers the cap base — that is reported separately as future-year benefit. Both numbers appear on every exhibit.
Which values enter the median — the comparable-basis rules
The statute's median is only as good as the values behind it. Our rules, from the statute and the district's own practice:
- Appraised value, except capped parcels enter at market. §42.26(d) commands that where a §23.23 or §23.231 limitation applies, "the value of the property subject to the suit and the value of a comparable property … must be the market value." Applied symmetrically to subject and comps.
- No fully-exempt parcels, either side. Parcels wholly exempt (charitable, religious, housing-finance, community land trust families) carry roll values no one defends; they are removed from the pool entirely.
- Comp-side hygiene. Parcels with value-distorting partial exemptions (abatement, freeport, historic, pollution control), parcels in active district-court litigation (their values are provisional), and parcels whose improvement stack mixes types (dominant type < 70% of improvement value) are excluded as comparables.
- No self-comparison, no double counting. A subject never appears in its own comp set; undivided-interest parcels are consolidated before screening.
TCAD's own Mass Appraisal Report describes its commercial equity review as a median of adjusted $/sf over comparable-property grids. Our exhibit argues in the appraiser's native format — the conversation is about comp selection, not whether the method is valid.
What it measured — Harris County, TY2024–2025
The identical screen, run on two prior years of noticed values, joined to HCAD's published ARB hearing outcomes. Formal hearings (conclusion codes FC/FN), evidence-grade cohorts, high confidence, protesters only:
| Formal ARB hearings · high confidence | n | Reduced | Mean cut | Cut >15% |
|---|---|---|---|---|
| TY2024 | ||||
| Flagged | 591 | 92.0% | 11.9% | 29.6% |
| Unflagged | 726 | 86.4% | 8.7% | 17.5% |
| TY2025 | ||||
| Flagged | 581 | 92.6% | 10.1% | 23.6% |
| Unflagged | 794 | 88.4% | 8.4% | 18.9% |
All protesters in high-confidence cohorts, by representation status:
| Year · representation | n flag / unflag | Reduced | Mean cut | Cut >15% |
|---|---|---|---|---|
| 2024 · agent | 1,589 / 3,044 | 86.7% vs 78.8% | 9.4% vs 7.1% | 21.3% vs 15.0% |
| 2025 · agent | 1,794 / 3,444 | 90.8% vs 85.3% | 8.8% vs 7.0% | 18.0% vs 14.4% |
| 2024 · pro se | 254 / 352 | 85.4% vs 68.8% | 13.8% vs 7.9% | 37.0% vs 18.2% |
| 2025 · pro se | 129 / 321 | 82.2% vs 76.3% | 10.7% vs 8.8% | 24.0% vs 19.6% |
About 90% of Harris commercial protesters use an agent, and flagged parcels are represented at the same rate (90–92%). The screen is not simply finding the parcels agents already work. Flagged parcels protest slightly more often (74–75% vs 69–71%).
Lift is measured among parcels that protested. Low-confidence cohorts show no lift and are never issued as evidence. Harris settles most commercial protests informally with single-digit cuts, so the base rate is high everywhere. Past outcomes in one county do not guarantee results in another; these are statistical estimates, not appraisals or legal opinions.
What a buyer receives
- The ranked list (CSV): parcel, owner, mailing address, confidence tier, cap-aware savings, lead class (never-represented · recently-lapsed with prior firm and expiry date · soft-lapsed, labelled · prior-protester · represented). Litigation parcels, public and institutional owners, and $25M+ assets are excluded (whales are quarantined with a written memo each).
- One-page equity exhibits for the top 100 ranked leads, prepared in the firm's name: subject summary, comp grid with every adjustment shown, median math, indicated value, cap-aware savings, full citations. Informal-ready as delivered.
- Formal-hearing packets on request: the same lead expanded to six pages — cover, analysis, per-comp detail, adjustment methodology, verbatim §41.43/§42.26 text, and provenance. Download a watermarked sample →
Validation
Every deliverable parcel is reconciled field-by-field to TCAD's certified export and a stratified sample is re-checked against the live county portal each season (our verification standard). Underneath that, the scoring is held to a from-scratch independent SQL recomputation (0 mismatches on the sampled sheets), deterministic hash-identical rebuilds, and mutation testing of the screen code (6,900 injected defects, zero survivors) — with the full method, counts, and taxonomy of every reconciled difference kept in the project's validation report.
Sources. Travis: TCAD certified appraisal export TY2026 (supp. 0, run 2026-07-18, layout v8.0.0.33), traviscad.org/publicinformation; TCAD agent-of-record 2023–2025, PIA delivery R010639-082426 (Aug 2026); Travis County Tax Office truth-in-taxation rate table (2025 adopted). Harris: HCAD PDATA real-property and ARB hearing files, TY2024–2026, download.hcad.org. Statute: Tax Code §41.43, §42.26, §23.231 (tcss.legis.texas.gov, retrieved 2026-08-22). Full calibration tables are delivered with every package.