Tavirex

Documentation

Understand how Tavirex analyzes property tax assessments, or integrate our analysis engine into your own application via the REST API.

Quickstart

Enter your property details and get an assessment analysis in under 5 minutes.

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Assessment Ratio Analysis

How we compute assessment-to-market ratios and coefficient of dispersion per IAAO standards.

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Comparable Sales Regression

Hedonic pricing model using property characteristics to estimate fair market value from recent sales.

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Appeal Probability Model

Logistic regression on historical appeal outcomes by jurisdiction, deviation, and property type.

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Net Savings Calculator

NPV of appeal savings over ownership horizon with tax rate escalation and appeal cost modeling.

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Monte Carlo Simulation

Sensitivity analysis on assessment outcomes, market value uncertainty, and tax rate trajectories.

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API Endpoints

POST/v1/calculate
POST/v1/compare
GET/v1/lookup?address=
GET/v1/pseo/:state/:county
POST/v1/signup
POST/v1/login
GET/v1/account
POST/v1/checkout

Authentication

All API requests require an API key passed via the X-API-Key header.

curl https://tavirex-api.smarttechinvest.com/v1/lookup?address=123+Main+St \
  -H "X-API-Key: tvx_your_api_key_here"

Assessment Ratio Analysis

The assessment-to-market ratio (AMR) compares your property's assessed value against its estimated fair market value:

AMR = Assessed Value / Estimated Market Value

An AMR significantly above 1.0 suggests potential over-assessment. We also compute the Coefficient of Dispersion (COD), which measures assessment uniformity across properties in your jurisdiction -- a key indicator of systematic assessment bias.

Our methodology follows the IAAO Standard on Ratio Studies (2013), the authoritative reference used by assessing officers nationwide.

Comparable Sales Regression

We estimate fair market value using a hedonic pricing model -- a regression that breaks down property value into contributions from individual characteristics: square footage, lot size, bedrooms, bathrooms, year built, and condition.

The model is trained on recent comparable sales within your jurisdiction, ensuring location-specific pricing that reflects your local market conditions.

Appeal Probability Model

Our appeal success probability model uses logistic regression trained on historical appeal outcomes from state equalization boards. Key features include:

  • Jurisdiction -- appeal success rates vary widely by county
  • Assessment deviation -- larger over-assessments correlate with higher success rates
  • Property type -- residential vs. commercial vs. agricultural
  • Representation -- self-represented vs. attorney vs. tax consultant

Net Savings Calculator

We compute the expected value of filing an appeal as:

EV = P(success) x E(reduction) x tax_rate x holding_period - appeal_costs

The result is discounted to net present value over your ownership horizon, with tax rate escalation modeling based on historical rate trends in your jurisdiction.

Monte Carlo Simulation

Rather than a single point estimate, Tavirex runs Monte Carlo simulations to produce confidence intervals on savings estimates. The simulation varies:

  • Assessment outcome variance -- how much might the assessor reduce?
  • Market value uncertainty -- comparable sales introduce estimation error
  • Tax rate trajectory -- will rates increase, decrease, or stay flat?

The result is a distribution of possible savings, giving you expected value, median, and worst-case estimates to support your decision.