What is permanent impairment
Permanent impairment is the formal medical assessment of how much body function you've permanently lost as a result of your injury. It's measured as a Whole-Person Impairment (WPI) percentage from 0% (no impairment) to 100% (extreme disability).
Australian schemes use various editions of the AMA Guides to the Evaluation of Permanent Impairment (most use the 4th, 5th or 6th edition; some have scheme-specific guides like the SIRA Guidelines in NSW). Assessment is by an accredited medical assessor — typically a specialist matched to the body region (orthopaedic surgeon for spine and limbs, psychiatrist for mental health, ENT for hearing, etc.).
WPI to dollar — indicative table
Lump-sum amounts vary by state and scheme. The table below is indicative of typical workers compensation amounts in NSW / VIC; other states use similar logic with different exact figures.
| WPI % | Indicative lump sum | Notes |
|---|---|---|
| 1–5% | $0 – $20,000 | Below threshold in some states; partial benefits in others |
| 6–10% | $15,000 – $50,000 | Threshold met in most states |
| 11–15% | $40,000 – $100,000 | NSW/WA common-law gateway met (15% WPI) |
| 16–20% | $80,000 – $200,000 | Stronger common-law claims |
| 21–30% | $150,000 – $400,000 | VIC "serious injury" threshold approached/met |
| 31–50% | $300,000 – $800,000 | Significant common-law access |
| 51%+ | $500,000 – $2,000,000+ | Catastrophic; lifetime care schemes may apply |
How WPI is assessed
- Referral to an accredited medical assessor matched to your body region
- Examination — physical examination, history, review of imaging and clinical records
- Application of AMA Guides — chapter-by-chapter assessment of specific body regions and impairment categories
- Combination — multiple impairments combined using the Combined Values Chart (not simple addition)
- Final WPI rating — single percentage that drives the lump sum
The assessment is typically the single most important medico-legal report in a claim. Treating doctor reports inform but don't determine the WPI — the accredited assessor's findings control.
Threshold gates by state
- NSW: 15% WPI for non-economic loss damages and common-law work-injury damages
- VIC: "Serious injury" certification (often 30%+ WPI for most categories)
- QLD: No WPI threshold for common-law damages (more accessible)
- WA: 15% WPI for common-law damages
- SA: 5% WPI minimum for lump-sum compensation
- NSW/QLD CTP motor accident: 10%+ WPI for non-economic loss in NSW; threshold tests vary
Tips to maximise the payout
- Don't accept early offers — settlements made before WPI assessment commonly understate the recovery
- Get formal assessment after stabilisation — your treating team must agree your condition is stable
- Combine impairments — multiple body regions assessed together (with Combined Values Chart)
- Consider psychiatric overlay — chronic pain conditions often qualify for separate psychiatric WPI
- Challenge low ratings — independent reassessment is available where appropriate
- Use a specialist lawyer for the assessment timing — the timing materially affects the rating