Primary sources used
Plain English answer
Does NSW use AMA5 for WPI?
NSW workers compensation permanent impairment assessments are made under the SIRA NSW permanent impairment guidelines. Those guidelines are largely based on the American Medical Association's Guides to the Evaluation of Permanent Impairment, 5th edition, often called AMA5. But in a NSW claim, the NSW guidelines are the controlling document. If the NSW guidelines modify or depart from AMA5, the NSW approach is the one that matters.
For an injured worker, the practical question is not, “Can I calculate my own WPI?” It is usually, “Did the assessor use the right accepted injury, body system, clinical material and NSW method before the insurer relied on the percentage?”
AMA5 is context
AMA5 supplies much of the underlying impairment framework, but workers should not treat it as a stand-alone NSW payout calculator.
SIRA Guidelines control
The NSW guidelines set the scheme-specific approach, including body-system chapters, assessor requirements and NSW modifications.
Evidence decides strategy
The percentage only becomes useful when it is checked against accepted injury wording, clinical records, surgery, causation and threshold consequences.
What this means in practice
A WPI report should do more than give a number. It should identify the condition assessed, explain why the injury is stable enough to assess, connect examination findings to the accepted workplace injury, and explain any deduction for prior or unrelated impairment. If those steps are missing or thin, the legal issue may be whether the insurer is relying on an incomplete assessment.
This is especially important where the percentage sits near a threshold. A small difference can affect Section 66 lump sum compensation, whether the worker is treated as having more than 20% WPI for some weekly payment consequences, or whether the file needs work injury damages threshold advice.
What an assessor is usually checking
Medical stability
The condition generally needs to have reached maximum medical improvement before permanent impairment is assessed. If surgery, treatment or recovery is still materially changing the injury, timing may matter.
Accepted injury wording
The assessment should match what is accepted or disputed in the claim. A report can be unreliable if it rates a narrower condition than the actual accepted injury.
Clinical method
The body system matters. Spine, upper limb, lower limb, hearing, vision, pain and psychological assessments do not all work the same way under the NSW guidelines.
Causation and deductions
Where degeneration, previous injury or non-work factors are raised, the report should explain the evidence for any deduction or causation conclusion.
Body-system issues workers should not gloss over
Spine injuries
Spine assessments can turn on diagnosis, imaging, neurological signs, surgery history, stabilisation and whether the report properly links clinical findings to the accepted injury. Do not assume an MRI finding alone decides the WPI percentage.
Upper limb injuries
Shoulder, elbow, wrist and hand assessments often require careful recording of movement, nerve findings, surgery, tendon injury, strength issues and treatment history. The report should explain the body part and method, not just state a percentage.
Lower limb injuries
Hip, knee, ankle and foot assessments may involve diagnosis-based findings, movement, gait, surgery and comparison with the uninjured side where relevant. Double-counting and missing surgery history are common issues to check.
Psychological injury
NSW does not simply use AMA5 Chapter 14 for psychiatric impairment. The NSW guidelines contain their own approach. Classification as primary or secondary psychological injury can materially change the compensation pathway.
Common problems in low WPI reports
- The assessor did not receive key imaging, operation notes, treating specialist material or updated certificates of capacity.
- The report records lighter pre-injury duties than the worker actually performed.
- A degenerative condition is treated as unrelated without explaining the work contribution or aggravation evidence.
- Neurological symptoms, surgery history, chronic pain features or psychological consequences are compressed into a short conclusion.
- The report gives a percentage but does not clearly explain the body system, method, deduction or threshold consequence.
Checklist before accepting or relying on a WPI percentage
How this connects to Section 66, weekly payments and work injury damages
A permanent impairment assessment can affect more than one part of the claim. It may be relevant toSection 66 lump sum compensation, to weekly payment issues where WPI thresholds matter, and to whetherwork injury damagesthreshold advice is needed. The same low assessment can also sit beside a treatment refusal, an unfair IME report, or a capacity dispute.
That is why the safer approach is to review the assessment as part of the whole file, not as a single isolated percentage. If the number affects a payment, settlement, treatment or damages decision, get advice before the insurer's version of the medical evidence becomes harder to undo.
Questions workers often ask
Does NSW workers compensation use AMA5 for WPI assessments?
NSW permanent impairment assessments are conducted under the SIRA NSW workers compensation guidelines. Those guidelines largely adopt AMA5 for many body systems, but the NSW guidelines control the assessment and prevail where they modify or depart from AMA5.
Can I use AMA5 to calculate my own WPI percentage?
You should not treat AMA5 as a self-scoring tool. WPI assessment is performed by trained medical assessors using the NSW guidelines, the accepted injury, clinical examination, records and any NSW-specific modifications. A worker can still check whether the report appears to have used the right assumptions and evidence.
Why does maximum medical improvement matter?
Maximum medical improvement means the injury has stabilised enough for permanent impairment to be assessed. If treatment, surgery or recovery is still materially changing the condition, the timing of a WPI assessment may need careful review.
What should I check in a low WPI report?
Check the accepted injury wording, job duties, diagnosis, imaging, surgery notes, maximum medical improvement, pre-existing condition deduction, body system assessed, and whether the assessor had the material that matters. The issue is usually whether the report is complete and methodologically reliable, not just whether the percentage feels low.
Can secondary psychological injury be assessed as permanent impairment?
SIRA guidance distinguishes primary psychological injury from secondary psychological conditions arising because of another work-related condition. Permanent impairment compensation is not available for secondary psychological injury, although those symptoms may still matter to treatment, weekly payments, capacity and work injury damages evidence.
General information only
This information is general in nature and is not legal advice. You should obtain advice about your own circumstances before relying on a WPI percentage, accepting a lump sum offer, or responding to an insurer decision.
Reviewed by NSW Work Injury Claims - a branch of Stephen Young Lawyers.
Related WPI and dispute pages
Need a low WPI assessment checked?
If the percentage does not match the injury history, accepted body part, surgery, imaging or work capacity evidence, get the report reviewed before signing or letting the insurer rely on it.