New Series Launch: Mass Appraisal Modeling Masterclass

Session 1: Sales Representativeness Testing — The First Rule of Valuation Modeling

Today, I’m launching the first session of our new mass appraisal modeling masterclass series — and it is FREE.

We start with the non-negotiable foundation: Sales Representativeness Testing.

Before calibrating an OLS engine, running spatial GIS regressions, or testing Price-Related Differential (PRD), every modeler faces a critical gatekeeper test: Is your sales sample truly representative of the population?

Skipping or rushing this foundational check compromises model integrity, induces systemic assessment drift, and leaves valuation models vulnerable during Value Adjustment Board (VAB) or judicial appeals.

Read Session 1 completely FREE today on Substack:

https://sidsom.substack.com/p/sales-representativeness-testing

Subscriber Note & Mission:

·        Session 1 is available completely free to establish our baseline diagnostic framework.

·        Sessions 2 through 10—covering time adjustment, dummy coding, ordinal coding, 2-pass outlier protocol (z-score), sales ratio analysis, OLS assumption tests, holdout tests, IAAO guidelines tests, and model application—will be exclusive to paid Substack subscribers. Of course, the Executive Summaries are always free for everyone on Substack and Patreon.

·        100% of all author proceeds from Substack subscriptions and book sales are donated directly to charitable causes, including Save the Children.

Read, share with your assessment teams, and let’s keep pushing mass appraisal toward econometric excellence.

#MassAppraisal #AVM #ValuationModeling #CAMA #Econometrics #Assessment #PropertyTax #SaveTheChildren #GIS #DataAnalytics