[nbouscal]

> Also interesting is that married people in the US of A experience a tax advantage when filing jointly

It's not quite that simple. Filing jointly confers a tax advantage when the couple makes relatively little, but becomes neutral as they earn more, and is actually a tax disadvantage when the couple makes a significant amount.

[dragonwriter]

The advantage to filing jointly is actually when the couple makes sufficiently different income, and the penalty is actually when they are close in income.

[nbouscal]

I was simplifying, and your simplification is more accurate, but neither simplification quite captures it. Both aspects play a role, with the amount the couple makes essentially scaling the benefit or detriment. If a couple makes the exact same amount but it's a low amount, there's zero detriment, but if it's a high amount there's a significant detriment. If they make very different amounts and it's a low amount, there's a significant benefit, but the size of that benefit decreases and can disappear entirely as they make more.

[EdwardDiego]

> It's not quite that simple.

That could be the catchphrase for the entire US tax code. :D