When Numbers Start Making Decisions · Season Four, “Things That Cannot Be Priced Directly” · Article 3
1. The body does not jump, but entitlement does
Imagine two New South Wales workers with similar injuries and lasting functional restrictions. After maximum medical improvement, one is assessed at 10 per cent whole person impairment and the other at 11 per cent. Their pain, movement and difficulty working may not change abruptly at that percentage point. For relevant physical-injury claims made on or after 19 June 2012, the legal consequence can: no section 66 permanent-impairment lump sum is payable at 10 per cent or below, while 11 per cent crosses the threshold.
SIRA’s July 2026 Workers Compensation Benefits Guide states that physical injury must exceed 10 per cent and summarises the threshold as 11 per cent. Primary psychological or psychiatric injury has a 15 per cent threshold. Permanent impairment percentages also interact with medical-expense periods, weekly payments and access to other claims. SIRA: Workers Compensation Benefits Guide
The law is not claiming that an 11 per cent body contains a new kind of injury absent at 10. It converts continuous functional loss into a standard percentage and connects that percentage to entitlement. Fairness depends on whether measurement error, consequences and review are designed together.
2. Whole person impairment is not total suffering
An accredited assessor applies the NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment after the condition has stabilised. The assessment examines relevant body systems, diagnosis, range of movement and prescribed criteria, then combines impairments according to the rules.
The purpose is consistency. It is not a direct measure of pain, lost income or diminished quality of life. Two workers with the same WPI can face very different occupational effects. A hand impairment affects a surgeon, musician and office worker differently. Identical spinal restrictions have different consequences for heavy labour and adaptable home-based work. Caring responsibilities, transport and employer accommodation are not fully inside the percentage.
WPI therefore measures one standardised dimension: permanent functional impairment of the whole person under the guideline. Compensation policy then decides which consequences attach. Calling the percentage a complete valuation of injury silently expands its purpose.
3. Why a threshold exists
A compensation scheme needs administrable boundaries. A minimum threshold directs lump-sum payments towards more substantial permanent impairment, limits disputes over very small results and helps maintain financial sustainability. A common guide reduces arbitrary differences among assessors.
The alternative is not a world without lines. A purely discretionary system could produce inconsistent outcomes and greater legal cost. Paying every percentage on a smooth scale would remove the entry cliff but still require a formula, minimum evidence and rules for multiple injuries.
The question is whether the cliff is proportionate. At 10 and 11 per cent, the measured difference is small while the entitlement difference begins at zero versus a statutory lump sum. That asymmetry makes accuracy and review near the boundary especially important.
The threshold can be defensible as a resource rule without being a natural description of injury. Government should say which of those claims it is making.
4. How one percentage point appears
Assessment is structured, but not free of judgement. The assessor determines diagnosis, stability, examination findings and the correct tables. Measurement of movement varies with pain, effort and technique. Different conditions may be combined, excluded or apportioned to pre-existing impairment under detailed rules.
Rounding can turn values into whole percentages. Guideline versions and the injury date affect which rules apply. A result near 10 therefore deserves a clear evidence chain: documents considered, findings, tables, deductions, combination and rounding.
Disagreement does not necessarily mean that one clinician acted improperly. It can reveal legitimate uncertainty within a standard. A fair system should distinguish factual error, methodological disagreement and later deterioration.
5. From 2026, one assessment carries more of the future
Reforms commencing on 1 July 2026 introduced a principal assessment framework. During the interim period to mid-2027, workers and insurers can arrange assessments, subject to independent legal advice, and an agreed principal assessment can establish entitlements across lump sum, weekly payments, medical expenses, commutations and work injury damages. SIRA: Assessment of permanent impairment
Further assessment after deterioration is restricted: the new arrangements require unexpected and material deterioration and an increase of at least 10 percentage points, with agreement or dispute processes. A single result therefore carries more future consequence than a one-off payment decision.
The policy may reduce repeated examinations and adversarial reassessment. It also increases the importance of high-quality evidence, independent advice and effective review at the first assessment. A worker assessed at 10 per cent cannot assume that ordinary gradual worsening will reopen the question.
6. Who can correct 10 and 11?
If worker and insurer cannot agree, a written decision must be provided and either party may refer the medical dispute to the Personal Injury Commission. Medical assessors and appeal pathways operate under legal criteria. Personal Injury Commission: Medical pathways
Review must be capable of changing the result, not merely explaining it. The worker needs access to the report, calculations and documents. Independent legal advice is important because the percentage affects multiple rights.
Error correction should be separated from deterioration. A mistaken table or omitted injury concerns the correctness of the original assessment. A later unexpected change concerns new evidence over time. Combining them can make a worker prove a large deterioration merely to fix an original mistake.
7. Designing the boundary more fairly
Several safeguards can coexist with the threshold:
- require explicit documentation of calculations and rounding;
- provide independent advice before a principal assessment;
- prioritise review of results close to consequential lines;
- audit assessor variation and overturned decisions;
- explain how one percentage affects every connected entitlement;
- keep error correction open even when later reassessment is restricted;
- review whether the cliff produces unjustifiable distributional effects.
A buffer or automatic second check near the line could reduce random boundary outcomes without abolishing the scheme’s basic structure.
Boundary auditing should compare assessments by body system, assessor, insurer and review outcome while protecting workers’ privacy. Unusual clustering at 10 per cent or large differences among assessors can signal interpretation problems even when individual reports appear compliant. Publication of de-identified distributions would let regulators see whether the threshold is changing assessment behaviour. Training and guidance could then address recurring disagreements before they become years of litigation for workers.
8. Impairment is a relationship, not a static remainder
Disability and work capacity arise from the relationship between a body, tasks, workplace, transport and support. WPI intentionally standardises the body-side of that relationship. Compensation, however, responds to a broader social and legal loss.
The percentage can serve as a portable interface between medicine and law. It should not be mistaken for the worker’s full experience or earning future. Other benefits and remedies exist precisely because one scale cannot carry every dimension.
Conclusion: keep the threshold, but do not review a borderline result only once
The 11 per cent threshold creates consistency and limits in a large compensation scheme. A common impairment guide is preferable to unstructured impressions.
My judgement is that a small measured difference should not bear a large, durable consequence without transparent calculation, independent advice and meaningful reconsideration. The 2026 principal-assessment reforms make those safeguards more urgent because the result can govern several future rights.
Ten and 11 are adjacent descriptions of functional impairment. The law may draw a line between them, but it must remain responsible for the cliff it creates.
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