The DI program was established in 1956 to provide monthly cash benefits to individuals unable to work because of severe long-term disability. To meet the definition of disability under the DI program, an individual must have a medically determinable physical or mental impairment that (1) has lasted or is expected to last at least one year or to result in death and (2) prevents the individual from engaging in substantial gainful activity (SGA). In addition, to be eligible for benefits, workers with disabilities must have a specified number of recent work credits under Social Security when they acquired a disability. Spouses and children of workers may also receive benefits. Benefits are financed by payroll taxes paid into the DI Trust Fund by covered workers and their employers, and the benefit amount is based on a worker’s earnings history. In November 2014, the program’s average monthly benefit for disabled workers was about $1,146. Historically, very few DI beneficiaries have left the program to return to work. To encourage work, the DI program offers various work incentives to reduce the risk a beneficiary faces in trading guaranteed monthly income and subsidized health coverage for the uncertainties of employment—including a trial work period, and an extended period of eligibility for DI benefits. These incentives safeguard cash and health benefits while a beneficiary tries to return to work. For example, the trial work period allows DI beneficiaries to work for a limited time without their earnings affecting their disability benefits. Each month in which earnings are more than $780 is counted as a month of the trial work period. When the beneficiary has accumulated 9 such months (not necessarily consecutive) within a period of 60 consecutive months, the trial work period is completed. The extended period of eligibility begins the month after the trial work period ends, during which a beneficiary is entitled to benefits so long as he or she continues to meet the definition of disability and his or her earnings fall below the SGA monthly earnings limit. SSA regulations require all DI beneficiaries to promptly notify SSA when: their condition improves, they return to work, or they increase the amount they work or their earnings. Program guidance directs DI beneficiaries to report to SSA right away if work starts or stops; if duties, hours or pay change; or they stop paying for items or services needed for work due to a disability. Beneficiaries may report work by fax, mail, phone, or in person at an SSA field office. SSA staff are required by law and regulation to issue a receipt acknowledging that the beneficiary (or representative) has given SSA information about a change in work or earnings, and documenting the date that SSA received the work report. After receiving information about work activity or a pay stub from a beneficiary, SSA staff have five days to input the information into the system—which creates a pending work report or pay stub report—and hand or mail a receipt to the beneficiary. Staff then have an additional 30 days to review the pending work report to determine if an additional action, such as a work continuing disability review (CDR), is needed to assess the beneficiary’s continued eligibility for DI benefits. See figure 1. SSA processes over 100,000 work reports or pay stubs annually. Benefit overpayments can occur when beneficiaries do not report work or SSA does not take action on work reports in an appropriate or timely manner. When a DI work-related overpayment is identified, the beneficiary is notified of the overpayment and may request reconsideration or waiver of that overpayment. SSA may grant a waiver request if the agency finds the beneficiary was not at fault AND recovery or adjustment would either defeat the purpose of the program or be against equity and good conscience, as defined by SSA. SSA’s DI cumulative overpayment debt has almost doubled over the last decade, growing from $3.2 billion at the end of fiscal year 2004 to $6.3 billion at the end of fiscal year 2014, according to SSA data. Cumulative overpayment debt is comprised of existing debt carried forward from prior years, new debt, reestablished debts (debts reactivated for collection due to re-entitlement or another event) and adjustments, minus debts that are collected or written off by SSA. Cumulative DI overpayment debt has continued to grow because in nine of the last ten years the debt added exceeded the total debt collected and written off. Specifically, over the 10 years reviewed, SSA added about $15.4 billion in debt, while collecting and writing-off $12.3 billion. According to preliminary data provided by SSA, the agency overpaid DI beneficiaries a total of about $20 billion during fiscal years 2005 through 2014, and more than half of this total ($11 billion) was a result of beneficiaries’ work-related earnings exceeding program limits. According to these data, each fiscal year an average of about 96,000 DI beneficiaries (or 28 percent of all beneficiaries overpaid each year) received excess benefits totaling $1.1 billion because their work activity exceeded program limits. The average work-related overpayment per beneficiary was almost $12,000 during this time period, ranging from $10,456 in fiscal year 2014 to $14,208 in fiscal year 2011. We are continuing to assess the reliability of these data as part of our ongoing work. SSA’s annual stewardship reviews provide limited insight into the causes of overpayments. Stewardship reviews are based on a sample of cases, and are used by the agency to report on the accuracy of benefit payments. In its stewardship reports, SSA uses the term deficiency dollars to quantify the effect of each individual deficiency in a case which could cause an improper payment. In its last six stewardship reports, SSA reported that deficiency dollars related to beneficiaries’ incomes being above DI program limits were consistently a leading cause of improper overpayments in the DI program. SSA also attributed some of these deficiencies to not taking appropriate or timely action to adjust payments when it was notified of beneficiaries’ work activity. However, GAO has not yet fully evaluated SSA’s methodology for conducting these reviews. Based on our discussions with SSA staff in field offices and teleservice centers, we identified a number of situations where beneficiaries report work or earnings, but staff may not enter information into the system, which is inconsistent with federal internal control standards, or may not provide a receipt, as mandated by law. Whether DI beneficiaries report work information in person or by fax, mail, or telephone to SSA field offices or the agency’s 800 teleservice line, in accordance with procedures, staff must manually enter the information into the system to initiate tracking and issue a receipt. Specifically, SSA representatives have five days to manually enter the information into the eWork system, which also generates a receipt to be mailed or given to the beneficiary. Issuing a receipt is required by law and valuable to the beneficiary for two reasons: (1) the beneficiary can review the receipt to ensure that the information is correct; and (2) a beneficiary who later receives an overpayment can produce work report receipts to prove that he/she properly reported work activity. This system also tracks pending work reports to ensure completion within 30 days. Tracking is critical for ensuring SSA promptly processes the work report and takes the actions needed to adjust a beneficiary’s benefits and minimize the chance of overpayments. However, in our work at several locations, SSA staff told us that if the eWork system is unavailable, or if the representative is busy, he or she may not enter the information and issue a receipt to the beneficiary. In addition, at one location, we learned that, until recently, SSA teleservice staff were using an alternate approach for sending work reports to the field office for manual entry and processing, instead of directly entering the information into the eWork system themselves. Work reports handled this way lack the controls in eWork; for example, they are not automatically tracked against the 30-day goal for work report completion. As such, they can be more easily missed or overlooked, and could be deleted or marked as completed without action being taken. Finally, claims representatives in the field office may also bypass the work report process entirely and initiate a work continuing disability review (CDR) instead. Some SSA claims representatives we interviewed told us that they skip the work report step and do a CDR instead because it is more efficient, but this means that the beneficiary does not receive a receipt. Stakeholder groups we interviewed have also observed problems with receipts, but SSA has limited data to assess this and other vulnerabilities in the work reporting process. In particular, stakeholders said that beneficiaries they work with do not always receive receipts, especially when reporting work by calling the 800 teleservice line. However, SSA’s ability to determine the extent of these vulnerabilities is hindered, in part, due to data limitations. SSA’s eWork system does not capture data that would help the agency determine how many work reports are filed by fax, mail, or in person. This system also does not allow SSA to determine how often staff go directly to a CDR without first completing a work report and issuing a receipt. Moreover, while SSA’s system archives copies of printed receipts, it does not provide aggregate data on receipts provided. So even though SSA officials noted that local offices have procedures in place to ensure the timely processing of information received by mail or fax, data limitations prevent SSA from knowing the extent to which receipts are provided within five days. Further, according to SSA officials, determining the extent to which 800 teleservice staff might be using alternative approaches for sending work reports to field offices would require a significant effort to match data between two different systems. Although the agency monitors work reports for timeliness, SSA lacks guidance for processing work reports through completion, and monitoring them for quality.