Metrics Explained
Every metric on this site is grounded in public data—from county records to municipal permits and property registries—then processed, standardized, and analyzed using transparent, well-documented formulas that you can review in my GitHub repository.
Test
This metric tells you what a typical square foot of living space in a given building (or neighborhood) costs—helping you quickly compare value across properties.
I calculate this by dividing the sale price of each unit by its square footage (as listed in county tax records), then averaging those values for the year. If there are fewer than three sales, I flag it as "insufficient data" to protect against outliers.
Why it matters: A building with a consistently higher price per square foot might signal strong demand, superior amenities, or prime location. Conversely, a lower value could indicate an opportunity—or red flags like deferred maintenance or unfavorable HOA conditions.
Median Price (by Year)
The midpoint of all unit sales over the year—half sold above this price, half below. Unlike the average, the median is less skewed by extreme outliers (like a penthouse sale).
This is useful when a building has varied unit types—studios alongside three-bedrooms—and you want a more balanced sense of the "typical" sale price.
CAGR (Compound Annual Growth Rate)
A measure of how fast a property is (actually) growing in value per year, on average. Imagine a unit sold for $300,000 five years ago; if it just sold for $450,000, the CAGR tells you the equivalent steady annual return you'd have earned on that investment.
I calculate this using the formula: [(Ending Value / Beginning Value)^(1 / Years)] - 1. Expressed as a percentage.
Value Appreciation
The increase in a property's value over time, shown as a cumulative total. Think of it as zooming out: how much did this building (or neighborhood) appreciate over the past year—five years—or ten?
I track this using repeat sales and year-over-year median trends. It's helpful for gauging if an asset is building equity consistently, or if gains are stagnating.
ROI (Return on Investment)
An estimate of the return you could earn by owning (and renting out) a unit in this building. ROI compares potential rental income to the purchase price, HOA fees, and operating costs.
Formula: [(Annual Rental Income - Annual Costs) / Total Investment] x 100
🔧 Coming soon: I plan to incorporate market rental income estimates and actual HOA costs to make this a more actionable metric that informs rental vs. buy decisions at the time.
My approach to Methodology
I'm not reinventing formulas—I'm standardizing the process. Every calculation draws from established real estate economics (CAGR, ROI) and reputable sources (county records, permit filings, tax rolls). My role is to extract and transform this data reliably—cleaning inconsistencies, flagging outliers, and organizing the data cleanly.
The process includes:
Data Collection
Scraping public records, sales histories, and permit data from county portals and municipal databases.
Data Cleaning
Removing duplicate records, correcting errors, standardizing addresses, and validating that the information is accurate and comparable.
Trend Building
Using historical data to build multi-year timelines that show price changes, volume shifts, and appreciation over time.
Analysis & Formulas
Applying straightforward statistical measures (median, average, CAGR) and custom formulas I've written that respect real estate norms, CAGR, and ROI frameworks.
Visualization
Presenting insights using heat maps, timelines, comparison tables, neighborhood overlays, and time-series graphs.
Data sources
I build this project using data from publicly available sources and publicly accessible data.
Primary Data Sources:
Miami-Dade County Open Data Hub:
Official downloadable datasets (sales records, property tax rolls, and zoning). gisweb.miamidade.gov/OpenDataHub/
Miami-Dade County Building Permits, Plans & Code Violations:
Comprehensive database tracking construction, renovation, and compliance history for individual properties. www8.miamidade.gov/Apps2/
Community Association Registry:
Annual filings from condo & HOA associations, including officer info and incorporation details (via FloridaStatutes 718/720). dos.myflorida.com/
Florida DBPR Official Records:
State repository for governing documents (declarations, amendments, bylaws) and association regulatory compliance reports. myfloridalicense.com/DBPR/
Public Records & Clerk of Court:
Searchable legal records (liens, special assessments, foreclosure filings) indexed by book and page. Miami-Dade Clerk's Portal: www2.miami-dadeclerk.com/
Miami Beach Public Records Portal:
Monthly building reports, fire safety, rental property data, and official municipal documents. miamibeach.gov/city-hall/public-records/
