From Small Counties to Big Data: Jonathan Williams on Modern Commercial Appraisal

Commercial appraisal has always been the quiet giant of the assessment world — complex, high-stakes, and often misunderstood even within our own profession. In Episode 66 of Assessment Matters, Jonathan Williams walks us through a career that has spanned small-county offices and big-data modernization efforts, offering a grounded perspective on where commercial appraisal has been and where it's headed.

Starting Small, Thinking Big

Jonathan's story begins where many of ours do: in a small county office where you wear every hat on the rack. In those environments, you learn commercial appraisal not from a textbook alone but from walking properties, reading leases, and building relationships with property owners who know you by name. Williams describes this foundation as irreplaceable — the kind of hands-on, boots-on-the-ground experience that builds intuition no algorithm can replicate.

But he's also candid about the limitations. Small counties often lack the transaction volume needed for robust statistical modeling. You're working with thin datasets, relying heavily on professional judgment, and sometimes defending values with more art than science. Williams doesn't frame this as a weakness — he frames it as a reality that shaped how he thinks about data today.

The Commercial Appraisal Challenge

For assessors working primarily in residential valuation, it can be easy to underestimate what commercial appraisal demands. Jonathan lays it out clearly: commercial properties are heterogeneous in ways that residential properties simply are not. A strip mall, a medical office building, and a warehouse may sit on the same block but require entirely different valuation approaches. Income capitalization, cost approaches, and sales comparison all come into play — sometimes on the same property.

Williams highlights the income approach as the backbone of modern commercial work, but he's quick to point out that the quality of income data varies wildly across jurisdictions. Some offices have mandatory income and expense reporting; others are left piecing together market rent estimates from whatever public information they can find. This disparity creates an uneven playing field, and it's one of the profession's most persistent challenges.

The Big Data Opportunity

This is where the conversation shifts from where we've been to where we're going. Jonathan Williams is clearly energized by the potential of big data in commercial appraisal — but he's not naive about it. He describes big data not as a silver bullet but as a set of tools that, when deployed thoughtfully, can dramatically improve accuracy, consistency, and defensibility.

What does big data look like in commercial appraisal? Williams points to several key areas:

• Market rent analytics drawn from aggregated lease data across regions, giving assessors a broader view of rental trends than any single jurisdiction could produce on its own.
• Cost modeling improvements fueled by construction data, material cost indices, and regional labor market information that update in near real-time.
• Sales verification and validation using multiple data sources to confirm transaction details, identify outliers, and flag non-arm's-length sales more efficiently.
• Predictive analytics that help assessors anticipate market shifts rather than simply reacting to them after the fact.

But Williams is careful to anchor the technology discussion in practical reality. Data is only as good as its governance. He stresses that assessors need to understand the provenance of their data, its limitations, and the assumptions baked into any model that uses it. Blindly trusting a dashboard is no better than blindly trusting a gut feeling.

Bridging the Gap Between Small and Large Jurisdictions

One of the most valuable threads in this conversation is Jonathan's perspective on equity across jurisdictions. Larger counties and metro areas naturally have more data, more resources, and more staff to dedicate to commercial valuation. Smaller counties often don't. Williams argues that big data and shared platforms have the potential to level this playing field — but only if the profession invests in collaboration.

He envisions a future where regional data-sharing agreements, standardized reporting frameworks, and shared analytical tools allow a small-county assessor to access the same quality of market intelligence as their counterparts in major metros. It's an ambitious vision, but Williams makes a compelling case that the technology is already there. What's needed is the institutional will to make it happen.

The Human Element

For all his enthusiasm about technology, Jonathan Williams keeps circling back to the people. Tools don't appraise properties — appraisers do. He emphasizes the importance of training, mentorship, and professional development, particularly for commercial appraisers who are often expected to master complex valuation methods with limited formal support.

He also speaks to the importance of communication — being able to explain a commercial value to a property owner, a board of review, or a court in plain language. Data and models can support your conclusion, but if you can't articulate the reasoning behind a value, the most sophisticated analysis in the world won't save you at a hearing.

Looking Ahead

Jonathan Williams offers a vision for commercial appraisal that is both optimistic and pragmatic. The profession is evolving, and the tools at our disposal are more powerful than ever. But the fundamentals haven't changed: understand the property, know your market, and be prepared to defend your work. Whether you're in a small county with a handful of commercial parcels or a metro area with thousands, those principles hold.

For assessors looking to sharpen their commercial appraisal practice, this episode is a thoughtful guide from someone who has navigated the full spectrum — from small-county pragmatism to big-data possibility — and found a way to bring both worlds together.