I think they mean if you are 1% away from a new tax bracket and get a 5% raise, 4% of that is at the higher tax bracket. So while you still make more money you

I think they mean if you are 1% away from a new tax bracket and get a 5% raise, 4% of that is at the higher tax bracket. So while you still make more money you make less than you would have if the entire 5% were in the lower bracket.