What is the test for determining whether a person is disabled by the time they apply for disability benefits?

1 To qualify for disability benefits, the claimant must establish that a medically determinable physical or mental impairment prevents her from engaging in substantial gainful activity and that the impairment is expected to result in death or to last for a continuous period of at least 12 months.... The claimant establishes a prima facie case of disability by showing that her impairment prevents her from performing her previous occupation.... The burden then shifts to the Secretary to show that the claimant can perform other types of work that exist in the national economy, given her residual functional capacity, age, education, and work experience.

Cotton v. Bowen, 799 F.2d 1403, 1405 (9th Cir.1986) (footnote and citations omitted).

2 Kellar reapplied for disability benefits while these proceedings were pending and was determined to be disabled, with benefits commencing April 3, 1987. However, we consider only the evidence of disability before the Secretary and his entitlement to benefits as of March 15, 1985, the date of his initial application. Cf. Sanchez v. Secretary of Health and Human Servs., 812 F.2d 509, 512 (9th Cir.1987) (claimant who reapplied for benefits entitled to benefits as of date of reapplication).