In a two-impairment scenario, the rating for the impairment combining method is:

• A. The rating for the greatest disability only
• B. The rating for the lesser disability only
• C. All of the rating for the greatest disability and approximately one half of the lesser disability
• D. The sum of both disabilities

Answer: (C)

In two impairments, impairment ratings are not simply added. The combining method uses a diminishing addition: take the larger impairment as the base and add about half of the smaller impairment. This reflects that the second impairment often overlaps with the first, so it contributes less incremental disability than the full amount.

For example, if one impairment is 40% and the other is 20%, the combined rating is roughly 40% plus half of 20% (about 10%), giving around 50% (the exact AMA approach yields about 52%). So the best answer is that you use the rating for the greatest disability plus approximately one half of the lesser disability.

This avoids both undercount (just the largest) and overcount (full sum) and aligns with how multiple impairments interact in the impairment rating method.