People present = residents + 0.5 × jobs located in the ZIP. That is the one documented assumption in the model. It treats residents as local customers. Commuters often are not.
The arithmetic. Demand is counted where people live (and, at half weight, where jobs sit). Establishments are counted where the shop is. If a ZIP is mostly bedrooms, some of that demand is spent in the employment ZIP next door — restaurants at lunch, gyms after work, grocery on the way home. The bedroom ZIP then looks sparse per person “present,” even when the trade area is served.
Each card on the radius search and the checker tags ZIP type from the jobs-to-residents ratio: residential, mixed, employment hub, destination. That tag is not zoning. It is a warning that the denominator and the numerator may not describe the same daily life.
This is why the site never turns a low count into advice. The same number can mean no shop, no space, or a street that empties at 9 a.m.
On a residential ZIP, compare it with nearby employment ZIPs on the same industry, and with a ~100,000-resident ring. If the ring is average and the bedroom ZIP is low, leakage is a candidate — not a verdict.
Cite: BizGapMap, “Bedroom ZIPs look empty by construction”, https://bizgapmap.com/stories/bedroom-zips/. Census ZBP 2023, ACS 2024 5-year. Supply counts, not advice. Reuse and CSV →
BizGapMap — free, no-login small-business saturation reports for major U.S. counties. Built entirely from public U.S. Census, BLS, and IRS data (ZBP 2023, ACS 2024 5-year, PEP 2024, LODES, QCEW, IRS SOI). No forecasts, no revenue guesses — withheld cells are marked, and the few derived counts are labelled as estimates.