To sort out some states' income tax systems, it can take an accounting degree. For others, a grade school graduate can figure it out, and for seven of the United States, there's no state income tax to calculate at all.
Forbes' Erin Carlyle and her crack team of researchers plow through the data and policy fine-print from the Washington, D.C.-based Tax Foundation's 2015 tax-return data, and generate this rankings of "The Worst States for Taxes." Carlyle writes:
To come up with the cleanest comparison possible, we calculated the effective tax rate for single taxpayers earning a taxable income of $50,000. Why this number? Well, it’s pretty average. From 2009 to 2013, the median American household income was $53,046, according to Census data, so it’s plausible that with some states’ standard deduction rates (which can range from $0 in Ohio to $10,250 for Wisconsin), a single-earner household making the median income might land at a taxable $50,000.