Workers’ Compensation · Primary-source case analysis

Nabors: Subtract Disability Percentages Before Calculating Indemnity

By Aneeta Mishra and Timothy Chan

Published May 1, 2026

Nabors rejects dollar subtraction in favor of percentage subtraction under Labor Code sections 4663 and 4664.

The overall rating was 80 percent

The worker had a final prior award of 49 percent and a later overall disability rating of 80 percent. The dispute concerned how to translate apportionment into the new award.

Percentages come first

The Board held that the percentage caused by other factors or previously awarded is subtracted from the overall permanent-disability percentage. The resulting percentage is then used to calculate indemnity.

Dollar subtraction would distort the statutory allocation

Subtracting the old award’s dollar value from the new overall award would compensate the combined disability rather than limit liability to the portion attributable to the later injury.

Disposition

The WCAB affirmed the 31-percent award produced by subtracting the prior 49-percent disability from the 80-percent overall rating.

Key takeaways

• Determine overall disability before apportionment.
• Express apportionment in percentage terms.
• Subtract the supported percentage before pricing the award.
• Treat overlap and proof of a prior award as separate threshold issues.