People often talk about how the federal income tax should not push people deeper into poverty. One way to measure how well the system performs in this regard is to look at how much a person or family can earn before income taxes kick in.
Current law's combination of standard deductions, personal exemptions, and credits yields some fairly odd results. This year, for a single person without children, the income tax threshold is $8,275; in other words, a person in this category will not pay income tax on the first $8,275 of wage earnings. For married people without children, the threshold is $12,950, or $6,475 per person--a marriage penalty.