A liberal group’s TV spot features a working mother who says she’s like “Warren Buffett’s secretary” and pays higher tax rates than “many billionaires and millionaires.” Not quite. With her $40,000 income and three kids, she’d actually pay a far lower rate than Buffett says he paid on his income. So, she’s not like his secretary. Furthermore, her rate would also be lower than the rate paid by the vast majority of those making more than $1 million a year.