This case study was originally prepared for presentation at the Introduction to the American Community Survey workshop of the 2009 annual meeting of the Population Association of America. It analyzes the comparability of ACS with Census Long-Form, including variable compatability (data and measures) and sample compatability (statistical inference), and focuses on changes in relationships between county poverty rates and structural covariates. In conclusion, it identifies four necessary user practices:

1. Review variable definitions.
2. Confirm variable universe.
3. Calculate MOE for derived variables.
4. Adjust standard errors for statistical inference.