	Introduction

The Social Security Administration (SSA) is responsible for administering two federal entitlement programs that provide income support to individuals with severe, long-term disabilities: Social Security Disability Insurance (SSDI) and Supplemental Security Income (SSI). SSDI is a work-related social insurance program that provides monthly cash benefits to nonelderly disabled workers and their eligible dependents, provided the workers accrued a sufficient number of earnings credits during their careers in jobs subject to Social Security taxes. In contrast, SSI is a need-based public assistance program that provides monthly cash payments to aged, blind, or disabled individuals (including blind or disabled children) who have limited assets and little or no Social Security or other income. In 2017, SSDI and SSI combined paid an estimated $199 billion in federally administered benefits to 14.5 million qualified disabled individuals and 1.5 million non-disabled dependents of disabled workers. Social Security Disability Insurance (SSDI)

Old-Age, Survivors, and Disability Insurance (OASDI), commonly known as Social Security, is a federal social insurance program established under Title II of the Social Security Act that provides workers and their families with a measure of protection against the loss of income due to the worker's retirement, disability, or death. The SSDI component of the program, which was enacted in 1956 and implemented in 1957, provides monthly benefits to statutorily disabled workers who are under Social Security's full retirement age (FRA) and to their eligible spouses, divorced spouses, minor children, student children, and disabled adult children. The Old-Age and Survivors Insurance (OASI) component of Social Security also provides benefits to eligible disabled dependents of retired workers and to eligible survivors of deceased beneficiaries and deceased insured workers. Although these individuals are not technically disability insurance beneficiaries, they are often included in the term SSDI , because they receive Social Security benefits due to a qualifying impairment. Cash Benefits

			Social Security Benefit Formula

Initial monthly Social Security benefits are based on an insured worker's creditable, career-average earnings in Social Security-covered employment or self-employment. Social Security is financed primarily by dedicated payroll and self-employment taxes levied on the earnings of workers in jobs covered by Social Security. SSI is commonly known as a program of "last resort" because claimants must first apply for most other benefits for which they may be eligible; cash assistance is awarded only to those whose assets and other income (if any) are within prescribed limits. The basic federal SSI payment is the same for all recipients and is reduced by most other income that an individual receives. Some states supplement the federal payment using state funds. Under the SSI program, an individual or couple must be aged, blind, or disabled to qualify for payments. For example, the program excludes the following:
the first $20 per month of any income (earned or unearned), other than unearned income based on need that is totally or partially funded by the federal government or by a non-governmental agency (e.g., TANF); the first $65 per month of earned income plus one-half of any earnings above $65; the first $30 per calendar quarter of infrequent or irregular earned income; the first $60 per calendar quarter of infrequent or irregular unearned income; food assistance provided under the Supplemental Nutrition Assistance Program (SNAP) and the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) program; energy assistance provided under the Low Income Home Energy Assistance Program (LIHEAP); housing assistance provided by most federally funded housing programs; federal tax refunds and advanced tax credits, including the Earned Income Tax Credit (EITC) and the child tax credit (CTC); assistance based on need that is funded wholly by a state or local entity; the first $2,000 received during a calendar year as compensation for participation in a clinical trial involving research and testing of treatments for a rare disease or condition; impairment-related work expenses (IRWEs) for disabled recipients and blind work expenses (BWEs) for blind recipients; and any income used to fulfill a plan to achieving self-support (PASS). Most adults are considered disabled for SSDI and SSI eligibility purposes if they are "unable to engage in any substantial gainful activity by reason of any medically determinable physical or mental impairment that can be expected to result in death or that has lasted or can be expected to last for a continuous period of not less than 12 months." Adults generally qualify as disabled for SSDI and SSI purposes if they have an impairment (or combination of impairments) of such severity that they are unable to perform any kind of substantial work that exists in significant numbers in the national economy, taking into consideration their age, education, and work experience.
The Social Security Administration (SSA) is responsible for administering two federal entitlement programs established under the Social Security Act that provide income support to individuals with severe, long-term disabilities: Social Security Disability Insurance (SSDI) and Supplemental Security Income (SSI). SSDI is a work-related social insurance program authorized under Title II of the act that provides monthly cash benefits to nonelderly disabled workers and their eligible dependents, provided the workers accrued a sufficient number of earnings credits during their careers in jobs subject to Social Security taxes. In contrast, SSI is a need-based public assistance program authorized under Title XVI of the act that provides monthly cash payments to aged, blind, or disabled individuals (including blind or disabled children) who have limited assets and little or no Social Security or other income. In 2017, SSDI and SSI combined paid an estimated $199 billion in federally administered benefits to 14.5 million qualified disabled individuals and 1.5 million non-disabled dependents of disabled workers.
SSDI is part of the federal Old-Age, Survivors, and Disability Insurance (OASDI) program, commonly known as Social Security. OASDI benefits are based on an insured worker's career-average earnings in jobs covered by Social Security and designed to replace a portion of the income lost to a family due to the worker's retirement, disability, or death. Workers become insured against these events by acquiring a certain number of earnings credits during their careers in covered employment or self-employment. The SSDI component of the program provides benefits to disabled workers who are under Social Security's full retirement age and to their eligible spouses and children. The Old-Age and Survivors Insurance (OASI) component also provides disability benefits to eligible disabled dependents of retired workers and to eligible disabled survivors of deceased beneficiaries and deceased insured workers. Although these individuals are not technically disability insurance beneficiaries, they are often included in the term SSDI because they receive Social Security benefits due to a qualifying impairment. SSDI and OASI disability benefits are paid from the Social Security trust funds, which are financed primarily by payroll and self-employment taxes levied on the earnings of covered workers.
SSI is a federal assistance program that provides needy aged, blind, or disabled individuals with a guaranteed minimum income to meet their basic living expenses. Although there are no work or contribution requirements to qualify for payments, the program is based on need and therefore is restricted to individuals with limited financial means. SSI is commonly known as a program of "last resort" because claimants must first apply for most other benefits for which they may be eligible; cash assistance is awarded only to those whose assets and other income (if any) are within prescribed limits. The basic federal SSI payment is the same for all recipients and is reduced by the amount of other income that an individual receives. Some states supplement the federal SSI payment with solely state funds. Unlike Social Security, SSI is financed by appropriations from general revenues.
Most claimants are considered disabled for SSDI and SSI eligibility purposes if they are unable to engage in any substantial gainful activity (SGA) by reason of any medically determinable physical or mental impairment that is expected to last for at least 12 months or to result in death. In 2018, the SGA earnings limit is $1,180 per month for most individuals. Claimants generally qualify if they have an impairment (or combination of impairments) of such severity that they are unable to perform any kind of substantial work that exists in significant numbers in the national economy, taking into consideration their age, education, and work experience. If a claimant's application for benefits is denied at any point during the disability determination process, the claimant has the right to appeal the determination or decision.