From Overlapping Disability and Unemployment Benefits Should be Evaluated for Potential Savings, a Government Accountability Office (GAO) study:
In fiscal year 2010, 117,000 individuals received concurrent cash benefit payments from the Disability Insurance (DI) and Unemployment Insurance (UI) programs of more than $850 million, which is allowable in certain circumstances under current program authority. While these individuals represented less than 1 percent of the total beneficiaries of both programs, the cash benefits they received totaled over $281 million from DI and more than $575 million from UI. ...
Under certain circumstances, individuals may be eligible for concurrent cash benefit payments due to differences in DI and UI eligibility requirements. Specifically, the Social Security Administration’s (SSA) definition of a disability involves work that does not rise to the level of substantial gainful activity (SGA). In 2010, a monthly income of $1,000 or more for a non-blind beneficiary generally demonstrated SGA. In contrast, the Department of Labor allows states’ determination of “able and available for work” eligibility criteria for UI benefits to include work that does not rise to the level of SGA. ... Reducing or eliminating overlapping or improper payments could offer substantial savings, though actual savings are difficult to estimate because the potential costs of establishing mechanisms to do so are not readily available.