Provides a framework for assessing variations in the premiums of plans offered in the Health Insurance Marketplaces (HIMs) across geography. Comparisons of premiums must include adjustments for several factors: plan type (metal level), enrollee age and family status, overall cost of living in the area, and the design of marketplace rating areas (state policy choices). What might appear to be differences showing plans in rural places to be more or less expensive than in urban places could shrink or even reverse after appropriate adjustments.