When you applied for disability, the Social Security Administration (SSA) asked you to provide the date when you became disabled, called your "alleged onset date" (AOD). If your claim is approved, Social Security will decide when it believes your disability began based on the medical evidence you provided to support your application— that day is called your "established onset date" (EOD).
Sometimes, your EOD (the onset date Social Security gave you) will be the same as your AOD (the date you gave Social Security)—if Social Security agrees with the date you think you became disabled. But sometimes your EOD will be after the date you claimed you became disabled (your AOD)—because Social Security doesn't agree that your AOD is when your disability first prevented you from working.
If Social Security gives you an EOD that's different from the date you said you became disabled on your application, it can dramatically impact the amount of money you can get in the form of:
If you're receiving SSI benefits, you can get back payments going back to the month after you filed for SSI (or the month after your protective filing date if you have one). (20 C.F.R. § 416.536.) But to get back pay that dates back to your application (or protected filing date), Social Security must decide that your EOD was before one of these dates.
For example, if you applied for SSI disability benefits on January 1, 2023, and your EOD is on or before your application date, you could get past-due back payments going back to February 1, 2023. But if Social Security says your EOD was after your application date—say June 1, 2023, then you'd only be eligible for back pay dating back to July 1, 2023.
If you're receiving SSDI, you can also get back payments going back to your application date (or your protective filing date). But SSDI recipients can also get up to 12 months of retroactive benefits for the time they were disabled before they applied. (20 C.F.R. § 404.621(a)(1).)
For example, if you applied for SSDI on January 1, 2023, you could get retroactive benefits going back to January 1, 2022, but only if your EOD is on or before August 1, 2021. (That's because there's a five-month waiting period that begins on your EOD and ends five months later, during which time you're not entitled to any benefits.)
So, to get the maximum 12 months of retroactive pay, your EOD would need to be 17 months before your application date (or your protective filing date). And if Social Security sets your EOD to a later date, you'd get less than a year's worth of retroactive benefits. For example, if Social Secuirty sets your EOD to 9 months before your application date, you'd only be entitled to 4 months of retroactive pay (9 months - 5 months).
(Learn more about how the five-month waiting period for SSDI works.)
Because of the differences in how Social Security calculates back pay for SSI and SSDI recipients, the effect of having an EOD (the date set by Social Security) that differs from your AOD (the date you said you couldn't work) will depend on the kind of disability benefits you're getting. The loss of benefits is usually greater with SSDI, since you could potentially get up to a year's worth of retroactive benefits.
Because you can only get SSI back pay dating back to your application (or protected filing date), the potential effect is less severe, but it can still be substantial.
Deciding whether or not to appeal a disability onset date is complicated. On the one hand, you stand to receive more money if you can get the SSA to change your EOD to an earlier date. But on the other hand, an appeal can have dire results if Social Security reverses your disability benefit award, denying you benefits altogether.
Any time you appeal a Social Security decision, a judge (or the Appeals Council) can take a fresh look at your entire case and deny your claim. So, if the reviewer thinks the prior decision-maker awarded benefits incorrectly, your disability award could be revoked.
There are times when appealing your EOD clearly isn't worth the risk of having your disability award reversed, like when:
Appealing your EOD is usually only worth the risk if a long time separates your AOD and your EOD and Social Security has made a clear error or you have new medical evidence showing your EOD should be changed. But you'll need to make sure any additional evidence you plan to use to support your case is solid.
Sometimes, it makes sense to appeal an established onset date (EOD) because you can show a clear error. There's specific evidence you'll want to gather to maximize your chances of winning. Here are the three most common errors that can lead Social Security to change an EOD on appeal.
If your earnings information is inaccurate, Social Security might have found that you were working, or performing "substantial gainful activity" (SGA), during months when you weren't actually working (or earning $1,470 a month). If the SSA uses the wrong numbers, you could be found ineligible for benefits for some months when you should have been eligible.
What would cause Social Security to use the wrong numbers? Sometimes, earnings show up in quarters when you didn't actually perform any work. Inaccurate earnings can happen due to situations like:
Regardless of the reason, if earnings show up in quarters where you didn't work, Social Security should change your established onset date (EOD) to a period where your earnings record indicates you weren't working at the SGA level. (SSR 18-1p, Discussion IIA.) It might be worth it to appeal your EOD if the difference would result in a significant amount of back pay.
If you decide to appeal, here are examples of evidence that might help prove your case:
When you receive your notice of decision, it will explain in detail why Social Security decided your claim the way it did. If the claims examiner or judge concluded that your EOD should be different than the disability onset date you claimed on your application (your AOD), your decision will state specifically why. Make sure you review this section carefully for accuracy.
It's not uncommon for Social Security to make errors about dates. It can make a huge difference in your EOD if:
If you find an error, make sure you're specific about it in your appeal, and then provide the information necessary to support your allegation that the information Social Security used to determine your EOD was wrong.
Sometimes, Social Security will issue a decision without all the applicable medical evidence. Such an error could happen if:
Regardless of the reason, if vital records are missing from your file, Social Security might choose the wrong EOD. If this happens, and you decide to appeal your EOD, you must be proactive and provide the missing evidence with your EOD appeal.
If you're considering appealing your EOD, you should probably talk with an experienced disability attorney or advocate first. A disability expert can review your case and discuss the pros and cons of appealing a "partially favorable decision" (one in which you won benefits, but they don't go all the way back to your AOD).
Learn more about when to consider hiring a disability attorney or advocate.
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