Starting this Wednesday, September
23, 2026, I am kicking off a brand-new, 10-part weekly series dedicated to
transforming mass appraisal practice through forensic econometric rigor.
Whether you are a CAMA modeler, chief
appraiser, assessment specialist, or valuation analyst, this series provides a
practical, step-by-step roadmap to building models that meet the highest
technical standards.
What to Expect Across the 10 Weekly Sessions:
·
Session
1 (Launch):
Representative Sales Sampling — Auditing sample integrity and P10–P90
percentile distribution stability before running a single model (the
non-negotiable first step!).
·
Sessions
2–5: Regression
Models — Calibrating four distinct OLS models using real county datasets,
featuring dummy location coding, time adjustments, ordinal encoding, 2-pass
regression, Z-score outlier trimming, and conditional variable parsimony.
·
Session
6: Sales Ratio
Analysis — Comparative diagnostics evaluating initial predictive accuracy
across all four models.
·
Session
7: Holdout
Testing — Rigorous cross-validation on out-of-sample sales to guard against
overfitting.
·
Session
8: OLS
Assumption Diagnostics — Comprehensive checks for multicollinearity (VIF), homoscedasticity,
non-linearity, and residual normality.
·
Session
9: IAAO
Guidelines & Performance Audits — Verifying compliance using COD, PRD,
PRB, and extended percentile diagnostics.
·
Session
10: Model
Application & Just Value Ratio Analysis — Roll generation across the
untransacted population and final assessment uniformity verification.
No
Representative Test = No Model.
Achieving
True BLUE Status
In this series, I will demonstrate how
proper specification and multi-pass diagnostic routines allow our models to
achieve Best Linear Unbiased Estimator (BLUE) status—bringing an
uncompromised econometric standard that legacy CAMA software environments
simply do not deliver.
Subscriptions
& Charitable Mission
· Subscription: $6/month
· Executive
Summary is always free for everyone on Substack.
· 100% Impact: All author proceeds from Substack subscriptions are donated directly to charitable organizations, including Save the Children.
· Stay tuned for the Session 1 link on Substack.