An article on the front of the Times "Review" section about taxes claims, "The United States does not have a particularly progressive tax system, ranking in the bottom half of the world, alongside nations like Italy and Turkey."
That's not accurate. Clive Crook, a centrist journalist, wrote in the Atlantic, a center-left publication, last year:
Income taxes in America are more progressive than in other rich countries--according to an authoritiative official study which, to my knowledge, has not been contradicted. The OECD's report "Growing Unequal", on poverty and inequality in industrial countries, includes a table that provides two measures of income tax progressivity in 2005. This is evidently the source of de Rugy's numbers. Here they are in an excel file. According to one measure, America's income taxes were the most progressive of the 24 countries in the sample, except for Ireland. According to the other, they were the most progressive full stop. (A more recent OECD report, "Divided We Stand", uses different data, a smaller sample of countries and a different measure of progressivity: the results are similar.)
Before you ask, this ranking takes account of employee-side payroll tax as well as the federal income tax.
The center-right economist Greg Mankiw, a regular Times contributor and the chairman of the Harvard economics department, has also written about this issue.