A letter report issued by the Government Accountability Office with an abstract that begins "As part of verifying if farm and conservation program participants had incomes below statutory limits--making them eligible to receive certain 2009 and 2010 program payments--reviews of tax returns by the U.S. Department of Agriculture's (USDA) Farm Service Agency's (FSA) state offices varied in quality. GAO's review of 115 tax return files from selected state offices found that some files met agency guidance and had no apparent errors. Other files did not meet agency guidance or contained errors, resulting in some potentially improper payments to participants whose incomes exceeded the limits. For example, GAO found errors in 19 of the 22 tax return files it reviewed from FSA offices in two states; one of these errors led to a potentially improper payment of $40,000. FSA headquarters does not monitor state offices' reviews of tax returns to ensure that the offices are applying program guidance consistently and making accurate eligibility determinations, even though federal standards for internal control direct agencies to monitor and assess the quality of performance over time. Also, 2008 Farm Bill provisions requiring a distinction between farm and nonfarm income make it difficult for agency …