.s . research and development credit . these and other factors , when compared to 2011 , increased the 2012 effective tax rate by 2.1 percentage points . factors that decreased the company 2019s effective tax rate year-on-year include international taxes as a result of changes to the geographic mix of income before taxes and adjustments to its income tax reserves . these factors , when compared to 2011 , decreased the effective tax rate 0.9 percentage points . the company files income tax returns in the u