Macroeconomic Advisers does the math on the compromise:
Based upon what is currently known of these three key [tax cut compromise] proposals, our preliminary analysis suggests that GDP growth in 2011 would be boosted by roughly ½ to ¾ percentage point. This is on top of the 3.7% growth of GDP anticipated for 2011 in our recently published forecast. Growth in 2012 could also be expected to be several tenths of a percentage point higher, with modest drag on growth in 2013, as the temporary provisions expire.