Medical documentation is the foundation of a disability claim. SSA decides most claims based almost entirely on what the medical record shows, not on how severe a condition feels day to day.
Whether you're preparing to file or trying to understand a denial, this page walks through exactly what kind of medical evidence SSA looks for, why an RFC opinion letter often matters more than any single test result, and how to fill gaps in an incomplete record.
A few terms first. SSA is the Social Security Administration. RFC is Residual Functional Capacity, what you can still do despite your limitations. MDI is Medically Determinable Impairment, a threshold concept covered below. For more on the broader application process, see our how to apply guide.