Understanding Value Differences: Competency

Time to Read: 4 Minutes
Technical Level: Moderate

Why it’s not art, not pure science, and not guesswork

Appraisal is often described as “part art, part science” — especially when two experts come to different conclusions. But that phrase oversimplifies what appraisers actually do and why they sometimes disagree. Appraisal is neither artistic expression nor exclusively formula-driven analysis; it’s a professional discipline grounded in judgment, facts, and standards. This article explains what competency really means, how it’s developed, and why it matters when appraisals diverge.

Appraisal is Applied Judgment

Competency in appraisal doesn’t mean knowing the answer at the outset. It means knowing how to define the problem, ask the right questions, find the relevant information, and apply the appropriate tools to reach a credible conclusion. Appraisers often work with limited or complex data, but they are expected to resolve uncertainty through research, supported judgment relevant to their assignment, and sound methodology. USPAP emphasizes objectivity for this reason: conclusions must be developed through a reliable process and grounded in evidence — not personal opinion.

Experience Informs Process

Appraisers may bring very different backgrounds to an assignment. One appraiser may focus on industrial properties and another may specialize in agricultural properties or subsidized housing. That experience helps them know where to look, but it doesn’t change the standards they’re required to follow. No matter how familiar an appraiser is with the property type, they still need to scope the problem correctly, perform the analysis, and support their conclusions with facts. Experience may accelerate the process, but it doesn’t replace it.

When Competency Is Met, Results Should Be Consistent

If two appraisers are both competent, apply the correct scope, and execute the process properly, their conclusions should generally fall within a reasonable range. Large differences often signal a problem: the assignment wasn’t well defined, the appraiser’s have different levels of competency, or the appraisal process wasn’t followed. Competency ensures that the appraiser knows how to handle the assignment, but it still requires full execution to produce a credible result.

---

The Bottom Line

While appraisal relies on data, analysis, and established methodologies, it differs significantly from laboratory science in both process and expectations. In a lab test, procedures are repeatable, variables are controlled, and outcomes are expected to converge when the test is correctly applied. The results, assuming valid methods, are designed to be replicable by any qualified technician.

Appraisal, by contrast, deals with markets which are influenced by human behavior, preferences, and conditions that are constantly changing and often incomplete. Appraisers must interpret imperfect data, reconcile competing indicators, and apply professional judgment in real-world environments where no two properties or circumstances are identical. The conclusions they reach are not universal truths, but reasoned opinions grounded in facts and shaped by context.

That’s why appraisal is considered a discipline of applied judgment, not formulaic science. The process must be structured and credible, but it’s not a mechanical outcome. Two appraisers may apply the same principles and still differ in interpretation if their judgment varies in how the data is weighted or how the problem is framed. What separates reliable appraisal from guesswork isn’t precision it’s transparency, methodology, and supportable reasoning.

If you’re comparing multiple appraisals with conflicting values, understanding how competency shapes the outcome can help you determine which opinion is more credible and why that difference matters.

---