This study examines the likely impact of the Arizona ballot initiative Proposition 208 tax increase on jobs, wages, interstate migration, tax revenue collections, state competitiveness, and small businesses in the state. We examine how similar types of tax increases over the past 30 years have worked in other states. We also provide an econometric projection for the number of jobs and amount of wages lost due to the rise in the state income tax on those Arizonans with adjusted gross income above $250,000 and $500,000 for joint filers. We find significant negative effects that would make Arizona residents poorer and the state’s economy less competitive.