In the context of a workers' compensation claim for a violent act, substantial cause means which of the following percentages of causation from all sources combined?

• A. 10-20%.
• B. 20-30%.
• C. 35-40%.
• D. 40-50%.

Answer: (D)

Substantial cause means a factor that contributes a meaningful portion to the overall causation of the injury when you add up all sources. In a workers’ compensation claim for a violent act, the violent act must be a substantial contributing factor relative to all causes, including any preexisting conditions and other contributing factors.

Here, substantial means roughly forty percent or more of the total causation. That’s why the forty-to-fifty percent range is the correct choice. Smaller shares—ten to twenty, twenty to thirty, or even thirty-five to forty—don’t reach the level considered substantial and therefore don’t meet the standard.