From a recent report by Social Security's Office of Inspector General (OIG) (emphasis added):
... Once a beneficiary becomes entitled to OASDI [Old Age, Survivors and Disability Insurance] benefits, SSA must update its records to reflect changes in the beneficiary’s circumstances. SSA refers to these updates as post-entitlement actions. T2R is SSA’s primary post-entitlement processing system. In some instances, T2R cannot process post-entitlement actions to update beneficiaries’ records and PC employees must do so.
When updates must be manually processed, T2R produces alerts. A PC employee must review the alert, correct any issues that prevented T2R from automatically processing the update, and make the necessary changes to the beneficiary’s record.
We identified 52,108 OASDI post-entitlement alerts T2R produced on or after January 1, 2017 and designated as processed and completed by PC employees from January 24 through February 6, 2019. We reviewed a random sample of 200 post-entitlement alerts to determine whether PC employees processed them correctly.
Of the 200 OASDI post-entitlement alerts we reviewed, PCemployees incorrectly processed 83 (42 percent). Of the 83 incorrectly processed alerts, 48 resulted in improper payments totaling $329,767 through May 2019. Based on our sample results, we estimate PC employees incorrectly processed approximately 555,000 alerts, resulting in approximately $1.3 billion in improper payments.
For 45 of the 83 alerts, PC employees took incorrect manual post-entitlement actions and did not update the beneficiaries’ records correctly. Our analysis showed that, in some instances, employees took incorrect manual actions because they did not—for unknown reasons—follow the provided instructions when they processed alerts. In other instances, employees may have incorrectly processed the alerts because of vague and generic alert language and corresponding written instructions.
Employees processed the remaining 38 alerts incorrectly because they cleared the alerts without taking corrective actions. SSA does not require that employees document why they did not take corrective action on alerts. Thus, we were unable to determine why employees cleared the alerts without taking action.
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The term "improper payment" makes you think that people were being overpaid and some were but further down you see that most of the "improper" payments were underpayments to claimants. This sounds like a big problem.