GIS/ValTech 2027

Assessment and Valuation GIS Toolbox for Nerds (Full-Day Workshop)
Monday, February 22, 2027 - 8:00 AM - 5:00 PM
Instructors: Lauren Voelker, Sr. Solution Engineer, Esri 
Dan Fasteen, Ph.D., Senior Research Scientist, Tyler Technologies

This hands-on workshop explores the modern geospatial toolkit for property valuation and assessment. We’ll explore how spatial analytics can enhance assessment accuracy, uncover neighborhood patterns, and support more defensible valuations.

We’ll start with the essentials—bringing your data into Pro and performing exploratory spatial analysis—before moving into advanced tools for valuation modeling. Learn how to apply exploratory regression, forest-based classification and regression, geographically weighted regression (GWR), spatially constrained multivariate clustering, and territory design tools to improve accuracy and insight in your valuation workflows.

We’ll also introduce the R-Bridge for extending analytical capabilities with custom scripts.

If time permits, we’ll conclude with a quick look at publishing results to your Web GIS organization and creating an interactive dashboard or app for visualization and sharing.

Whether you’re a valuation professional curious about analytics or a GIS nerd eager to apply data science to property assessment, this session will expand your technical skill set and show how modern spatial methods can elevate your valuation practice.

This session challenges how we think about certainty in ratio studies, exploring why point estimates and traditional confidence intervals may not tell the whole story about assessment performance. Participants will learn how improved approaches, including Bayesian methods, can better account for uncertainty and lead to clearer, more defensible valuation decisions.

Paul Bidanset, Founder & Executive Director, Center for Assessment Research and Technology (CART)
Peadar Davis, Peadar Davis, PhD, MRICS, Senior Lecturer, Ulster University
Luc Hermans, Global Chief Officer/Data Scientist, Netherlands Council for Real Estate Assessment

Keywords: Statistics & Ratio Studies, Mass Appraisal & Valuation Modeling, Intermediate

This session explores two often-overlooked challenges to assessment equity: capturing the unique building and unit characteristics that drive condominium values and accurately valuing high-end non-residential properties where data and traditional methods can fall short. Through real-world examples, presenters will show how better data, classifications, and valuation approaches can uncover hidden inequities and improve consistency across the tax base.

The REAL Equity Problem in Assessment
Keywords: Assessment Equity, Mass Appraisal & Valuation Modeling, Intermediate
Kevin Keene, Consultant, Keene Mass Appraisal Consulting


Valuing Vertically: Modernizing Condominium Mass Appraisal in Philadelphia
Jimmy Williams, MSc, CPE, CBP, CCA, Mass Appraisal Supervisor, Philadelphia Office of Property Assessment, PA
Alex Raju, CPE, Supervisor of Analytics, Philadelphia Office of Property Assessment, PA
Anthony Ruocchio, CPE, Deputy Administrator, Philadelphia Office of Property Assessment, PA

Geographically weighted gradient boosting brings location into machine learning by allowing relationships to vary across space rather than assuming the same model applies everywhere. This advanced session explores how the approach works, why spatial variation matters in mass appraisal, and what real-world case studies can teach us about building and interpreting locally responsive valuation models.

Luke Jorgensen, Mass Valuation Machine Learning Specialist, Thimgan & Associates

Keywords: Artificial Intelligence & Machine Learning, GIS & Spatial Analysis, Mass Appraisal & Valuation Modeling, Advanced

The Netherlands is giving vertical equity analysis a modern makeover, moving from outdated tools to new metrics, international standards, and cutting-edge research. This session explores how Dutch assessors are incorporating IAAO standards, new equity measures, and practical online tools to better understand, monitor, and address vertical inequity.

Luc Hermans, Global Chief Officer/Data Scientist, Netherlands Council for Real Estate Assessment – Netherlands
Gijs Deen, Data Analyst, Netherlands Council for Real Estate Assessment - Netherlands

Keywords: Statistics & Ratio Studies, Assessment Equity, Intermediate

Machine learning can do more than predict values. It can help us understand why properties behave similarly, identify meaningful comparables and adjustments, and reveal how markets organize themselves across space. This session moves from opening the machine learning black box to drawing data-driven neighborhood boundaries, showing how explainable AI, information theory, and even techniques borrowed from gerrymandering can turn complex algorithms into practical market insight.

Gerrymandering for Explainability: Automated Neighborhoods Using Gerrymandering Algorithms and Information Theory
Keywords: Artificial Intelligence & Machine Learning, GIS & Spatial Analysis, Intermediate
John Kossa, Data Scientist, Lee County Property Appraiser’s Office - TX

Explainable Machine Learning for Mass Appraisal: From Prediction to Market Insight
Keywords: Artificial Intelligence & Machine Learning, Mass Appraisal & Valuation Modeling, Advanced
Joe Wehrli, Enterprise Architecture Manager, Tyler Technologies - OH

Machine learning may produce great valuations, but can you explain and defend them when someone challenges the result? This session puts ML on the witness stand, exploring how models perform against IAAO ratio study standards, how complex predictions can be translated into explanations taxpayers and appeals boards can understand, and how assessors can build the documentation needed to make machine learning valuations defensible

Will Jarvis, CEO and Founder, Valuebase - NC

Keywords: Artificial Intelligence & Machine Learning, Assessment Appeals, Statistics & Ratio Studies, Beginner

AI is moving quickly from research papers and experimental models into the everyday work of assessment offices. This session explores what the research tells us about AI and machine learning in property valuation, then looks at how emerging tools help assessors automate workflows, uncover insights, improve valuations, and make better decisions while keeping human judgment, transparency, and public trust at the center.

The AI-Assisted Assessor: How Technology is Reshaping Appraisal & Assessment
Keywords: Artificial Intelligence & Machine Learning, Change Management & Technology Adoption, Beginner
Andrew Harrison, Vice President, State & Local Government Sales, Schneider Geospatial

AI in Property Valuation: Research Practice and Emerging Applications
Keywords: Artificial Intelligence & Machine Learning, Mass Appraisal & Valuation Modeling, GIS & Spatial Analysis, Beginner
Daniel Fasteen, Ph.D., Senior Research Scientist, Tyler Technologies