During the fourth of the five-step sequential disability determination process, the Vocational Expert ("VE") takes the claimant's assigned Residual Functional Capacity ("RFC") for work and matches it against the job data in the Dictionary of Occupational Titles ("DOT") to determine if the claimant can competitively hold a job that he or she held within the past fifteen years.
For the first time in the sequential process, the claimant's RFC for work is measured according to actual work previously performed. This is also the first time when the full public policy underlying the disability program is tested: given the client's RFC for work, can she or he actually engage in competitive work? If it is determined that the claimant is able to perform past relevant work, then the process stops there and the claimant is found not disabled.
If the claimant reaches the fifth step, the burden shifts to the SSA to demonstrate that reference to the Medical- Vocational Guidelines (the "Grids") dictates that either the claimant is able to perform other substantial gainful employment or that a significant number of jobs that the claimant is able to perform is available in the national economy.