When VA grants a claim for service connection, each service-connected disability is assigned a percentage according to VA’s rating schedule. If a veteran is service-connected for multiple disabilities, the combined evaluation determines that rate at which the veteran is paid. Many veterans are surprised that the combined evaluation is not always equal to the sum of the individual evaluations. This is because VA uses the combined ratings table. The premise behind the combined ratings table is that a veteran cannot be more than 100 percent disabled, therefore each additional disability is detracting from the remaining ability rather than simply adding to the disability.
For example, a veteran who is 60 percent disabled is 40 percent not disabled. If that veteran is awarded another 10 percent disability evaluation, then VA will take 10 percent of the remaining 40 percent and consider the veteran 64 percent disabled and 34 percent not disabled. This 64 percent would be rounded down and the veteran would be paid at the 60 percent rate. If a veteran were 60 percent disabled and received an additional 20 percent disability evaluation, VA would consider the veteran 68 percent disabled and 32 percent not disabled. This evaluation would be rounded up to 70 percent. So according to VA math, 60 percent plus 10 percent is 60 percent, while 60 percent plus 20 percent is 70 percent.
The higher the evaluation, the more it takes to get to the next level. For example, if a veteran is service connected at 90 percent, it would take five additional 10 percent disabilities to reach 95 percent disabled, which would round up to a 100 percent evaluation.