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Engineering tools

Property valuation with adjustment factors and regression

Organise the valuation into stages: subject property, sample, model, checks, and value with a report. Choose the analytical approach to suit the market, purpose and quality of the comparables, reviewing data sources and diagnostics.

Open the tool

The app and these introductory pages are available in Portuguese, English and Spanish.

What the tool calculates

  • Comparison using adjustment factors, regression and a CatBoost option based on boosted trees
  • Assessment of substantiation grades I, II and III, identifying satisfied criteria and missing information
  • Search for and record comparable properties, documenting the sources of listings
  • Diagnostic plots, equation and intervals appropriate to the selected approach

What you enter

  • Property characteristics, location and valuation purpose
  • Sample of comparable properties with characteristics, prices, sources and dates
  • Selected approach, such as comparison using adjustment factors, regression or the Brazilian evolutionary valuation method (método evolutivo)

What you receive

  • Estimated value and confidence interval, where applicable to the approach
  • Substantiation grade I, II or III when the applicable criteria are met
  • PDF valuation report and documentation of comparable property sources

References and limits of applicability

  • ABNT NBR 14653-1:2019 — Asset valuation, Part 1: General procedures
  • ABNT NBR 14653-2:2011 — Asset valuation, Part 2: Urban real estate (substantiation grade, confidence interval width)

Checks and considerations

  • Sample provides insufficient support for the chosen approach or intended substantiation grade
  • Outliers, a heterogeneous sample or extrapolation require review of the data and model

How it works

The approach must suit the property, purpose and market. Adjustment factors require evidence relevant to the location and period; regression requires appropriate diagnostics and a valid application domain. A confidence interval for the mean or median is not a mandatory range for every asking price. Automated assessments and generated reports do not replace a site inspection, technical review or professional responsibility.

Example of use

To value an urban property, gather comparables with documented sources and dates, then review their location, type and characteristics. Choose an approach supported by the data, review the diagnostics and explain limitations in the report. Do not tune the model simply to reproduce an asking price.

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