Impairment rating

What is an impairment rating?

An impairment rating expresses permanent loss of function as a percentage, either of a specific body part or of the whole person.

It is assigned by a physician after the condition has stabilized, using published guidelines that standardize how findings translate into percentages.

The purpose is comparability. Without a common method, one physician's assessment of a shoulder injury could not be measured against another's.

It measures impairment rather than disability. What a person can no longer do in their particular occupation is a separate question.

It is frequently confused with disability, and the distinction matters considerably in how a claim is presented.

How is a rating determined?

The assessment draws on measurable findings rather than reported symptoms.

Different guideline editions can produce different percentages, so the edition used is worth confirming.

• Measured range of motion compared against normal values
• Strength testing and documented atrophy
• Imaging findings and any surgical history
• Nerve conduction results where nerve involvement is claimed
• Published guideline tables converting findings into percentages
• Whether the part is scheduled or assessed as the whole person

Where is the rating used?

Most directly in workers' compensation, where a permanent partial disability award is calculated from the percentage assigned.

In injury litigation it functions as corroboration rather than as a formula, since no schedule converts a rating into damages.

It nonetheless helps a jury understand severity, because a percentage is more concrete than a description of limitation.

It also gives both sides a common reference point in settlement discussion.

What are its limits?

It does not capture what an impairment means for a particular life. The same rating applies to a labourer and an office worker whose situations differ entirely.

It also does not measure pain, which can be disabling without producing measurable loss of motion or strength.

This is why earning capacity and non-economic damages are assessed separately rather than derived from the rating.

Presenting the rating alongside evidence of what the person can no longer do avoids the impression that the percentage is the whole story.

Common questions

Does a rating determine what my case is worth?

No. In litigation it is one piece of evidence among many. Only workers' compensation converts a rating directly into a benefit calculation.

Can I dispute a rating?

Yes. Competing evaluations are common, and the dispute is resolved by the compensation judge or by a jury depending on the forum.

Does a low rating mean a minor injury?

Not necessarily. A modest rating can still end a physically demanding career, which is why occupational impact is assessed separately.