Minor Late Disclosure Without Prejudice Does Not Require Exclusion; CAMA Assessments Retain a Strong Presumption of Validity

Introduction

In H. Kenneth Johnston II v. Todd Ernst, in his official capacity as the Laramie County Assessor, 2026 WY 2 (Jan. 6, 2026), the Wyoming Supreme Court reviewed a residential property tax valuation dispute arising from Laramie County. H. Kenneth Johnston II (taxpayer, pro se) challenged the County Assessor’s valuation of his home, primarily arguing that the assessed value should reflect either (i) his 2013 purchase price, (ii) neighborhood sale prices, or (iii) a realtor’s market evaluation.

The case presented two recurring issues in Wyoming property tax appeals: (1) whether the County Board of Equalization abused its discretion by admitting the Assessor’s exhibits when the taxpayer received them fewer than 30 days before the hearing; and (2) whether the taxpayer met his burden to overcome the presumption that the Assessor’s valuation, derived via the State’s Computer Assisted Mass Appraisal (CAMA) system, was correct and lawful.

Summary of the Opinion

The Court affirmed the County Board of Equalization, the State Board of Equalization, and the district court. It held:

No abuse of discretion occurred when the County Board admitted the Assessor’s evidence, where the Assessor mailed disclosure 30 days before hearing and the taxpayer received it 27 days before hearing, asserted no prejudice, and the governing rule makes exclusion discretionary.
Substantial evidence supported the County Board’s decision upholding the valuation, and the decision was in accordance with law, because the Assessor used the mandated CAMA system and the taxpayer did not present credible evidence of misuse, incorrect inputs, or unlawfulness. The Court rejected the taxpayer’s claim that “actual sale values” should control, reiterating that exclusive reliance on actual sales prices may undermine constitutional uniformity and equal treatment.

Analysis

Precedents Cited

The Opinion is best understood as an application—and tightening—of existing Wyoming administrative-review and ad valorem taxation principles. The Court relied heavily on recent valuation-review cases and established administrative-law standards.

1) Appellate posture and substantial-evidence review

Contango Res., LLC v. Fremont Cnty., 2025 WY 29 and State v. Uinta Cnty. Assessor, 2024 WY 106: The Court reaffirmed that when a county board decision is appealed, the Supreme Court’s review “is focused on the County Board’s decisions,” with no deference to the State Board of Equalization or district court. These cases frame the lens through which the Court tested both the evidentiary ruling and the valuation merits.
Gray v. Converse Cnty. Assessor, 2023 WY 116: Quoted for the definition of substantial evidence and the “rational premise” standard, reinforcing that the reviewing court does not reweigh evidence but asks whether a reasonable mind could accept the record as adequate to support the board’s findings.

2) Discretion in evidentiary and “discovery-like” exchange rulings

Wearmouth v. Four Thirteen, LLC, 2024 WY 116 and Groskop v. S&T Bank, 2020 WY 113: Cited for the abuse-of-discretion framework applicable to “mechanisms used to control discovery” and sanctions. Although this is an administrative context, the Court borrowed civil-discretion principles to assess whether exclusion was required.
Airtouch Commc'ns, Inc. v. Dep't of Rev., 2003 WY 114 and Clark v. State ex rel. Wyo. Workers' Safety and Comp. Div., 968 P.2d 436 (Wyo. 1998): Used to underscore that administrative agencies have broad discretion in evidentiary matters in contested cases. This supports the holding that exclusion is not automatic even when an exchange deadline is missed.
Hutton v. Dykes, 2025 WY 94 and Davidson-Eaton v. Iversen, 2022 WY 135: Anchored the proposition that the appellant bears the burden of showing an abuse of discretion and that discretion is abused only when the decision exceeds the bounds of reason under the circumstances. The Court treated “prejudice” as the key practical circumstance: a short delay plus no demonstrated prejudice does not exceed the bounds of reason.

3) Constitutional uniformity, valuation methods, and presumptions favoring the assessor

Thunder Basin Coal Co. v. Campbell Cnty., 2006 WY 44: Quoted for the constitutional command that assessors must adopt a rational appraisal method, equally applied, producing essential fairness—linking directly to Wyoming Constitution Art. 15, § 11.
Mountain Vista Ret. Residence v. Fremont Cnty. Assessor, 2015 WY 117 and Helmut J. Mueller Ltd. P'ship v. Treanor, 2018 WY 131: Provided the “strong presumption” in favor of assessor valuations and the notion that officials are presumed to have exercised honest judgment consistent with law and rules. These cases also ground the “shifting burdens” framework applied here.
Gray v. Wyo. State Bd. of Equalization, 896 P.2d 1347 (Wyo. 1995): Central to the Court’s rejection of a “sales price controls” theory. The Opinion invoked Gray’s warning that reliance on actual sales prices in lieu of uniform methods “may well lead to discrimination and lack of equality and uniformity.” This case supplied the constitutional logic for why the assessor may use standardized, statewide methods and why a single property’s purchase price is not dispositive.
Britt v. Fremont Cnty. Assessor, 2006 WY 10 (quoted via Contango Res., LLC v. Fremont Cnty.): Reinforced that appellate courts do not decide which appraisal method is best; they decide whether substantial evidence supports the chosen method. This principle directly undercut Mr. Johnston’s argument that alternative methods should have been preferred over CAMA.
McInerney v. Kramer, 2023 WY 108: Cited to justify declining to address an undeveloped constitutional claim lacking cogent argument and authority, emphasizing that pro se status does not relieve litigants from basic briefing requirements.

Legal Reasoning

1) Late disclosure: discretionary exclusion turns on reasonableness and prejudice

The governing statute, Wyo. Stat. Ann. § 39-13-109(b)(i), requires parties to exchange evidence and witness disclosures “no later than thirty (30) days” before the county board hearing. Importantly, the statute itself does not specify a mandatory remedy for lateness. The implementing rule, Rules, Wyo. State Bd. of Equalization, ch. 7, § 8 (2021), states that failure to timely exchange “may result in exclusion” at the discretion of the county board or hearing officer.

On the facts, the Assessor mailed disclosure 30 days before hearing, and Mr. Johnston received it 27 days before hearing. The Court treated the practical consequence (three fewer days) as insufficient to mandate exclusion absent a showing that the short delay impaired preparation. Because Mr. Johnston claimed no prejudice (no inability to review, no surprise theory, no request for continuance, no demonstrated unfairness), the Board’s choice to admit the exhibits did not exceed the bounds of reason.

The ruling effectively clarifies that the 30-day exchange requirement is enforced through discretionary case management, not automatic suppression, and that a complaining party should be prepared to articulate concrete prejudice (or request a continuance) rather than rely on the deadline alone.

2) Valuation merits: strong presumption + shifting burdens + statewide uniformity

The Court’s valuation analysis proceeds in three linked steps:

Uniformity and fair market value are constitutional/statutory commands. Wyoming Constitution Art. 15, § 11 requires equal and uniform valuation and taxation. The legislature requires valuation at fair market value and directs the Department of Revenue to prescribe appraisal methods: Wyo. Stat. Ann. § 39-13-103(b)(ii).
The CAMA system is the rule-based default for most property. Department of Revenue rules require CAMA for “all real and personal property” except when narrative or other recognized supplemental appraisals substitute: Rules, Wyo. Dep't of Revenue, Ch. 9, § 7 (2016). The Assessor testified to the CAMA workflow (replacement cost new less depreciation, then market adjustment by neighborhood sales ratios) and to reliance on Marshall & Swift costing inputs and statewide CAMA use.
The presumption and shifting burdens govern who must prove what. Under Contango Res., LLC v. Fremont Cnty. and Helmut J. Mueller Ltd. P'ship v. Treanor, the assessor’s CAMA-based value enjoys a strong presumption. The taxpayer bears an initial burden to present credible evidence that the valuation is wrong or unlawful. Only then does the burden shift to the assessor to defend, with the taxpayer retaining the ultimate burden of persuasion by a preponderance.

Applying that framework, the Court held Mr. Johnston did not meet his initial burden. He did not show incorrect property characteristics were entered into CAMA, did not show misuse of CAMA, and did not identify legal rules requiring sales prices to be the sole measure of fair market value for assessment purposes. His realtor’s market evaluation, while relevant information, did not itself establish CAMA error or unlawful methodology—especially where the assessor’s evidence showed CAMA considered neighborhood sales as part of the ratio/market adjustment component.

The Court also rejected Mr. Johnston’s argument that the Assessor’s post-appeal adjustments undermined validity. The Opinion treated the reassessment after appeal as consistent with mass appraisal practice: appeals trigger closer review, which may yield justified corrections (here, quality rating adjustment and siding correction) without implying the original method was unlawful or arbitrary.

Impact

Evidence-exchange disputes will be prejudice-driven. This case strengthens the practical lesson that missing the 30-day exchange window does not automatically exclude evidence. Parties seeking exclusion should build a record of prejudice: surprise, inability to prepare, need for continuance, or unfair disadvantage. County boards can—and likely will—admit evidence absent such a showing.
CAMA challenges must be technical and rule-based. Taxpayers disputing assessments should expect that generalized fairness arguments, historic purchase prices, or “sales should control” theories will not overcome the presumption. Successful appeals will more often turn on demonstrating incorrect data inputs (e.g., square footage, condition/quality, features), misapplied multipliers, inconsistent neighborhood coding, or noncompliance with Department of Revenue rules.
Reinforces uniformity over individualized transaction pricing. By invoking Gray v. Wyo. State Bd. of Equalization, the Opinion signals continued skepticism toward valuation approaches that elevate a single transaction price over standardized methods designed to treat similarly situated properties similarly.
Encourages assessors to correct during appeals without fear of “admission.” The Court’s acceptance of post-appeal individualized review supports administrative flexibility: assessors can refine valuations in response to appeals while maintaining the presumption of correctness, so long as adjustments remain anchored to CAMA/rules and are explained in the record.

Complex Concepts Simplified

CAMA (Computer Assisted Mass Appraisal): A standardized system used to value many properties efficiently and consistently. It typically estimates replacement cost (what it would cost to build the structure new), subtracts depreciation, then adjusts to local market conditions using neighborhood sales data.
Mass appraisal vs. individualized appraisal: Mass appraisal values many properties using consistent models and data; individualized appraisal is property-specific and may use narrative approaches. Wyoming rules generally require CAMA (mass appraisal), with limited exceptions.
Strong presumption of correctness: Courts presume the assessor followed the rules and acted with honest judgment. The taxpayer must first produce credible evidence of error or illegality before the assessor must do more to justify the value.
Shifting burdens: The taxpayer must first rebut the presumption (initial burden). If successful, the assessor must defend the valuation (responsive burden). The taxpayer still must ultimately prove the valuation is unlawful or incorrect.
Substantial evidence: Not “the best evidence” or “most evidence,” but enough relevant evidence that a reasonable person could accept it as supporting the decision. The court does not re-try the case or reweigh credibility.
Abuse of discretion: A highly deferential standard. A decision is reversed only if it exceeds the bounds of reason under the circumstances. In evidence-exchange disputes, showing concrete prejudice is often decisive.
Uniformity and equality in taxation: Wyoming’s Constitution requires that properties be valued and taxed uniformly within classes. Methods that rely too heavily on isolated sale prices can create unequal treatment among similar properties.

Conclusion

Johnston v. Ernst reinforces two practical rules for Wyoming property tax appeals. First, minor noncompliance with the 30-day exchange timeline does not require evidence exclusion where the governing rule makes exclusion discretionary and the complaining party shows no prejudice. Second, CAMA-based assessments enjoy a strong presumption of validity; taxpayers must present credible, method-focused evidence (data errors, rule violations, or misapplication) to overcome that presumption. By reemphasizing constitutional uniformity and the limited role of courts in second-guessing appraisal methodology, the Opinion further stabilizes Wyoming’s mass-appraisal framework against challenges grounded primarily in purchase price or neighborhood sales comparisons untethered to CAMA error.