How Michigan Signals Collects County Data: Sources, APIs, and Update Frequency

Michigan Signals tracks dozens of metrics across ten Michigan counties. A common question from users and researchers: where does the data come from, how is it collected, and how often does it update? This guide answers those questions for each major data category on the platform.

Demographics: Census Bureau

Population: Annual estimates from the Census Bureau's Population Estimates Program (PEP). Michigan Signals uses Vintage 2019 estimates for 2010–2019 and Vintage 2023 estimates for 2020–2023. PEP estimates are released each June for the prior year. After the 2020 decennial census, the Census Bureau discontinued county-level population API endpoints; Michigan Signals fetches the Vintage 2023 CSV directly from the Census data repository.

Income and poverty: From Census SAIPE (Small Area Income and Poverty Estimates). Annual estimates released each December covering the prior year. SAIPE provides the most current annual income and poverty figures available at the county level — more timely than ACS 5-year estimates.

Educational attainment, household size, foreign-born population, race/ethnicity: From the ACS 5-year estimates (2023 vintage — covering 2019–2023) via the Census Bureau API. Released annually each December.

Employment: BLS LAUS

County unemployment rates come from the Bureau of Labor Statistics Local Area Unemployment Statistics (LAUS) program. Michigan Signals currently stores county unemployment data in JSON files, which are refreshed when the data pipeline is run. LAUS releases monthly county data with approximately a one-month lag; annual averages are available for full calendar years. The current data covers through early 2026.

Housing: Zillow and HUD

Home values: Zillow Home Value Index (ZHVI) for single-family residences and condos, middle tier (33rd to 67th percentile), smoothed and seasonally adjusted. Zillow publishes county-level CSV files updated monthly. Michigan Signals pulls these directly from Zillow Research public data files.

Rent index: Zillow Observed Rent Index (ZORI) for all homes (SFR, condo, multifamily). Same methodology and update cadence as ZHVI.

For-sale inventory and new listings: Also from Zillow Research monthly CSV files.

Owner occupancy, vacancy rate, cost-burdened renters: From Census ACS 5-year estimates (2023 vintage) via the Census API.

HUD Fair Market Rents: From HUD's public API. Annual figures for 1-bedroom and 2-bedroom units, used to set Section 8 voucher payment standards.

Health: CDC PLACES

Health behavior and outcome estimates come from CDC PLACES 2024, which provides small-area estimates at the county and census tract level derived from the Behavioral Risk Factor Surveillance System (BRFSS). Michigan Signals tracks seven measures: obesity, smoking, fair/poor health status, uninsured rate, diabetes, depression, and physical inactivity. PLACES releases updated county estimates annually.

Healthcare provider counts (primary care and mental health practices per 100k) come from the Census Bureau County Business Patterns program (2022 vintage). CBP releases annual establishment counts by NAICS code at the county level.

Economy and Crime

Economy metrics include business counts and employment from CBP, SAIPE income data, and ACS economic characteristics. Crime data is compiled from Michigan State Police annual reports and the FBI Uniform Crime Reporting program for available years.

Update Frequency

Michigan Signals data is refreshed when the pipeline is run, which happens when new data vintages are released or when accuracy improvements are made. The most recent full refresh was run in June 2026, incorporating:

• Census ACS 2023 (released December 2024)
• Census SAIPE 2023 (released December 2024)
• Census CBP 2022 (released 2023–2024)
• CDC PLACES 2024 (released 2024)
• Zillow ZHVI/ZORI through April 2026
• BLS LAUS through April 2026

Data Accuracy and Limitations

All data sources have limitations. ACS estimates carry margins of error. CDC PLACES uses modeled estimates, not direct survey counts for every county. Zillow's ZHVI is an index, not a median sale price. Michigan Signals displays source labels and descriptions on every metric to help users understand what each figure measures and where it comes from.

Questions about specific metrics can be explored on any county dashboard. Start with any of the ten tracked counties: Kalamazoo, Kent, Wayne, Oakland.