Data Quality

6 articles

Census API in Python: Pulling ACS Data With Validation Checks

A Python workflow for pulling ACS data from the Census Bureau API, with the validation checks that catch bad data before it reaches the analysis.

Feb 2026 · Methodology

How to Validate GTFS Feeds Before Routing Breaks

A Python workflow for catching the transit data problems that structural checks miss. Six validation layers from download fallbacks to multi-agency sanity checks.

Feb 2026 · Methodology

Spatial Analysis with GeoPandas: From Joins to Autocorrelation

A spatial analysis workflow that starts with point-to-polygon joins and builds toward spatial weights, autocorrelation testing, and LISA cluster detection…

Feb 2026 · Methodology

Data Quality: From 49% to 12% Mobility Deserts

We found 49% of California census tracts were mobility deserts. After getting complete transit data, the corrected figure is 12%.

Nov 2025 · Transit Equity

400 Labels to 94% Accuracy: Validating Grocery Store Data

Google Places returned thousands of 'grocery stores.' Many weren't. Here's how a classifier separates real grocery stores from gas stations and liquor stores.

Oct 2025 · Methodology

The Retail Density Paradox: Why More Stores Mean Worse Data

A verification method for EBT acceptance across the roughly 28,800 California stores in the USDA list, where more retailers means messier, not better, data.

Oct 2025 · Methodology