When you apply for Social Security Disability Insurance (SSDI) benefits, one of the most important details in your application is your alleged onset date (AOD) — the date you claim your disability began. This date impacts not only when your benefits start, but also how much you may receive in back pay if your claim is approved.
But what happens when the Social Security Administration (SSA) disagrees with your onset date? This situation is more common than you might think, and it can significantly impact both your benefit amount and your Medicare eligibility timeline.
What Is the Onset Date?
Your onset date is the date you became unable to work due to your medical condition(s). Often, this is the last day you worked, but that’s not always true. Some people stop working for non-medical reasons, or they attempt to return to work briefly before realizing their condition still prevents them from working full-time.
Choosing the correct onset date is critical. It must be consistent with your work history and supported by medical evidence showing when your condition became severe enough to prevent substantial gainful activity.
Why the Onset Date Matters
Your onset date affects several important parts of your SSDI benefits:
- When your benefits begin
- How much back pay you’re eligible to receive
- When you qualify for Medicare coverage
Keep in mind, SSDI benefits include a mandatory five-month waiting period from the established onset date. Also, SSA can only pay retroactive benefits for up to 12 months before the application date — assuming you're found to be disabled long enough to qualify.
Why SSA Might Dispute Your Onset Date
The SSA reviews your medical records, work history, and any attempts to return to work to verify whether your alleged onset date is supported by evidence. If there are gaps in treatment, inconsistent work activity, or unclear documentation about when your condition became disabling, the SSA might set a later onset date than the one you claimed.
A later onset date could reduce the amount of back pay you’re eligible for, push back your first benefit payment, and delay your Medicare eligibility.
Example: How the Right Onset Date Can Impact Your Benefits
Let’s say you stopped working on May 5, 2024, due to a health condition but attempted to return to work later in the year, only to stop again on December 12, 2024, when your condition worsened.
Without legal guidance, you might assume your onset date is December 12, 2024 — the last time you stopped working. But with the right legal support, you could argue that your disability actually began on May 5, 2022, and that your return to work was an unsuccessful work attempt.
This matters because an earlier approved onset date can result in several additional months of benefits — potentially worth thousands of dollars.
What to Do if SSA Assigns a Different Onset Date
If the SSA disputes your onset date and assigns a later date, you have the right to appeal that decision. However, you’ll need to provide:
- Detailed medical evidence that supports when your disability actually began
- Work history records that show any work attempts were unsuccessful due to your condition
- Statements from medical providers that explain the progression of your condition
Working with an experienced Social Security Disability attorney can be critical. A qualified attorney will carefully review your medical records and work history to develop a strategy that supports the earliest possible onset date — and represent you throughout the appeals process.
Let MCV Law Help You Maximize the Benefits You Deserve
At MCV Law, we’ve helped hundreds of clients successfully navigate complex Social Security Disability claims — including disputes over onset dates. Our experienced attorneys understand how to build strong, evidence-based cases that reflect the true impact of your disability.
If your onset date is under review — or your claim has been denied — contact us today for a free consultation. We’re here to protect your rights and help you secure the benefits you deserve.