Apportionment allocates a percentage of permanent impairment to the incident and the remainder to preexisting conditions, prior injuries, or intervening events. It requires evidence of the pre-incident baseline.
The AMA Guides provide methodology where apportionment is permitted.
Alternative Names:
Impairment Apportionment, Causation Apportionment
Why it Matters?
Apportionment is the mechanism that limits exposure where a claimant had documented preexisting pathology, and it depends entirely on establishing the pre-incident baseline. Without prior records or imaging, an examiner cannot credibly apportion, which is why obtaining the complete prior treatment history is the predicate. States that prohibit apportionment leave the defendant responsible for the entire resulting impairment regardless of prior condition.
Frequently Confused with
Related terms
Frequently asked questions
What is required to apportion impairment?
Do all states permit apportionment?
