What is the test for denial of disability benefits?

The Commissioner makes this assessment by employing a five-step analysis outlined in 20 C.F.R. 404.1520. See also Tackett v. Apfel, 180 F.3d 1094, 1098-99 (9th Cir. 1999) (describing five steps). First, the Commissioner determines whether a claimant is engaged in "substantial gainful activity." If so, the claimant is not disabled. 20 C.F.R. 404.1520(b) (2019). Second, the Commissioner determines whether the claimant has a "severe impairment or combination of impairments" that significantly limits the claimant's physical or mental ability to do basic work activities. If not, the claimant is not disabled. Id. 404.1520(c). Third, the medical evidence of the claimant's impairment is compared to a list of impairments that are presumed severe enough to preclude work; if the claimant's impairment meets or equals one of the listed impairments, benefits are awarded. Id. 404.1520(d). If not, the claimant's residual functional capacity is assessed and the evaluation proceeds to step four. Id. 404.1520(e). Fourth, the Commissioner determines whether the claimant can do his or her past relevant work. If the claimant can do their past work, benefits are denied. Id. 404.1520(f). If the claimant cannot perform his or her past relevant work, the burden shifts to the Commissioner. In step five, the Commissioner must establish that the claimant can perform other work. Id. 404.1520(g). If the Commissioner meets this burden and proves that the claimant is able to perform other work that exists in the national economy, benefits are denied. Id.