NSW workers compensation guidelines for the evaluation of permanent impairment

These guidelines explain permanent impairment assessment in the NSW workers compensation system. This is the fourth edition of these guidelines, published in April 2016.

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The State Insurance Regulatory Authority (SIRA) has issued the 4th edition of the NSW workers compensation guidelines for the evaluation of permanent impairment (Guidelines) for assessing the degree of permanent impairment arising from an injury or disease within the context of workers’ compensation. When a person sustains a permanent impairment, trained medical assessors must use the Guidelines to ensure an objective, fair and consistent method of evaluating the degree of permanent impairment.

The Guidelines are based on a template that was developed through a national process facilitated by Safe Work Australia. They were initially developed for use in the NSW system and incorporate numerous improvements identified by the then WorkCover NSW Whole Person Impairment Coordinating Committee over 13 years of continuous use. Members of this committee and of the South Australia Permanent Impairment Committee (see list in Appendix 2) dedicated many hours to thoughtfully reviewing and improving the Guidelines. This work is acknowledged and greatly appreciated.

The methodology in the Guidelines is largely based on the American Medical Association’s Guides to the Evaluation of Permanent Impairment, 5th Edition (AMA5). The AMA guides are the most authoritative and widely used in evaluating permanent impairment around the world. Australian medical specialists representing Australian medical associations and colleges have extensively reviewed AMA5 to ensure it aligns with clinical practice in Australia.

The Guidelines consist of an introductory chapter followed by chapters dedicated to each body system.

The Introduction is divided into three parts. The first outlines the background and development of the Guidelines, including reference to the relevant legislative instrument that gives effect to the Guidelines. The second covers general assessment principles for medical practitioners applying the Guidelines in assessing permanent impairment resulting from work-related injury or disease. The third addresses administrative issues relating to the use of the Guidelines.

As the template national guideline has been progressively adapted from the NSW Guideline and is to be adopted by other jurisdictions, some aspects have been necessarily modified and generalised. Some provisions may differ between different jurisdictions. For further information, please see the Comparison of Workers’ Compensation Arrangements in Australia and New Zealand report, which is available on Safe Work Australia’s website.

Publications such as this only remain useful to the extent that they meet the needs of users and those who sustain a permanent impairment. It is, therefore, important that the protocols set out in the Guidelines are applied consistently and methodically. Any difficulties or anomalies need to be addressed through modification of the publication and not by idiosyncratic reinterpretation of any part. All queries on the Guidelines or suggestions for improvement should be addressed to SIRA at

1. Introduction

Part 1 - Intent and legislative basis for these guidelines

1.1 For the purposes of the WorkCover Authority of NSW*, the 4th edition of the NSW workers compensation guidelines for the evaluation of permanent impairment (the Guidelines) are made under s376 of the Workplace Injury Management and Workers Compensation Act 1998 (WIMWC Act). The Guidelines are to be used within the NSW workers compensation system to evaluate permanent impairment arising from work-related injuries and diseases.

The Guidelines adopt the 5th edition of the American Medical Association’s Guides to the Evaluation of Permanent Impairment (AMA5) in most cases. Where there is any deviation, the difference is defined in the Guidelines and the procedures detailed in each section are to prevail.

1.3 - 1.5 Development of the Guidelines

1.3 The Guidelines are based on a template that was developed through a national process facilitated by Safe Work Australia. The template national guideline is based on similar guidelines developed and used extensively in the NSW workers compensation system. Consequently, provisions in the Guidelines are the result of extensive and in-depth deliberations by groups of medical specialists convened to review AMA5 in the Australian workers compensation context. In NSW it is a requirement under s377(2) of the WIMWC Act that the guidelines are developed in consultation with relevant medical colleges. The groups that contributed to the development of the Guidelines is acknowledged and recorded at Appendix 2. The template national guideline has been adopted for use in multiple Australian jurisdictions.

1.4 Use of the Guidelines is monitored by the jurisdictions that have adopted it. The Guidelines may be reviewed if significant anomalies or insurmountable difficulties in their use become apparent.

1.5 The Guidelines are intended to assist a suitably qualified and experienced medical practitioner in assessing a claimant’s degree of permanent impairment.

Part 2 - Principles of assessment

1.6 The following is a basic summary of some key principles of permanent impairment assessments:

a. Assessing permanent impairment involves clinical assessment of the claimant as they present on the day of assessment taking account the claimant’s relevant medical history and all available relevant medical information to determine:

  • whether the condition has reached Maximum Medical Improvement (MMI)
  • whether the claimant’s compensable injury/condition has resulted in an impairment
  • whether the resultant impairment is permanent
  • the degree of permanent impairment that results from the injury
  • the proportion of permanent impairment due to any previous injury, pre-existing condition or abnormality,
  • if any, in accordance with diagnostic and other objective criteria as outlined in these Guidelines.

b. Assessors are required to exercise their clinical judgement in determining a diagnosis when assessing permanent impairment and making deductions for pre-existing injuries/conditions.

c. In calculating the final level of impairment, the assessor needs to clarify the degree of impairment that results from the compensable injury/condition. Any deductions for pre-existing injuries/conditions are to be clearly identified in the report and calculated. If, in an unusual situation, a related injury/condition has not previously been identified, an assessor should record the nature of any previously unidentified injury/condition in their report and specify the causal connection to the relevant compensable injury or medical condition.

d. The referral for an assessment of permanent impairment is to make clear to the assessor the injury or medical condition for which an assessment is sought – see also paragraphs 1.43 and 1.44 in the Guidelines.

1.7 Medical assessors are expected to be familiar with chapters 1 and 2 of AMA5, in addition to the information in this introduction.

1.8 The degree of permanent impairment that results from the injury/condition must be determined using the tables, graphs and methodology given in the Guidelines and the AMA5, where appropriate.

1.9 The Guidelines may specify more than one method that assessors can use to establish the degree of a claimant’s permanent impairment. In that case, assessors should use the method that yields the highest degree of permanent impairment. (This does not apply to gait derangement – see paragraphs 3.5 and 3.10 in the Guidelines).

1.10 - 1.14 Body systems covered by the Guidelines

1.10 AMA5 is used for most body systems, with the exception of psychiatric and psychological disorders, chronic pain, and visual and hearing injuries.

1.11 AMA5 Chapter 14, on mental and behavioural disorders, has been omitted. The Guidelines contain a substitute chapter on the assessment of psychiatric and psychological disorders which was written by a group of Australian psychiatrists.

1.12 AMA5 Chapter 18, on pain, is excluded entirely at the present time. Conditions associated with chronic pain should be assessed on the basis of the underlying diagnosed condition, and not on the basis of the chronic pain. Where pain is commonly associated with a condition, an allowance is made in the degree of impairment assigned in the Guidelines. Complex regional pain syndrome should be assessed in accordance with Evaluation of permanent impairment arising from chronic pain in the Guidelines.

1.13 On the advice of medical specialists (ophthalmologists), assessments of visual injuries are conducted according to the American Medical Association’s Guides to the Evaluation of Permanent Impairment, 4th Edition (AMA4).

1.14 The methodology for evaluating permanent impairment due to hearing loss is in Hearing Loss of the Guidelines, with some reference to AMA5 Chapter 11 (pp 245–251) and also the tables in the National Acoustic Laboratories (NAL) Report No. 118, Improved Procedure for Determining Percentage Loss of Hearing, January 1988.

1.15 - 1.16 Maximum medical improvement

1.15 Assessments are only to be conducted when the medical assessor considers that the degree of permanent impairment of the claimant is unlikely to improve further and has attained maximum medical improvement. This is considered to occur when the worker’s condition is well stabilised and is unlikely to change substantially in the next year with or without medical treatment.

1.16 If the medical assessor considers that the claimant’s treatment has been inadequate and maximum medical improvement has not been achieved, the assessment should be deferred and comment made on the value of additional or different treatment and/or rehabilitation – subject to paragraph 1.34 in the Guidelines.

1.17 - 1.20 Multiple impairments

1.17 Impairments arising from the same injury are to be assessed together. Impairments resulting from more than one injury arising out of the same incident are to be assessed together to calculate the degree of permanent impairment of the claimant.

1.18 The Combined Values Chart in AMA5 (pp 604–06) is used to derive a percentage of whole person impairment (WPI) that arises from multiple impairments. An explanation of the chart’s use is found on pp 9–10 of AMA5. When combining more than two impairments, the assessor should commence with the highest impairment and combine with the next highest and so on.

1.19 The exception to this rule is in the case of psychiatric or psychological injuries. Where applicable, impairments arising from primary psychological and psychiatric injuries are to be assessed separately from the degree of impairment that results from any physical injuries arising out of the same incident. The results of the two assessments cannot be combined.

1.20 In the case of a complex injury, where different medical assessors are required to assess different body systems, a ‘lead assessor’ should be nominated to coordinate and calculate the final degree of permanent impairment as a percentage of WPI resulting from the individual assessments.

1.21 - 1.22 Psychiatric and psychological injuries

1.21 Psychiatric and psychological injuries in the NSW workers compensation system are defined as primary psychological and psychiatric injuries in which work was found to be a substantial contributing factor.

1.22 A primary psychiatric condition is distinguished from a secondary psychiatric or psychological condition, which arises as a consequence of, or secondary to, another work related condition (eg depression associated with a back injury). No permanent impairment assessment is to be made of secondary psychiatric and psychological impairments. As referenced in section Multiple impairments, impairments arising from primary psychological and psychiatric injuries are to be assessed separately from the degree of impairment that results from physical injuries arising out of the same incident. The results of the two assessments cannot be combined.

1.23 Conditions that are not covered in the Guidelines - equivalent or analogous conditions

1.23 AMA5 (p 11) states:

Given the range, evolution and discovery of new medical conditions, these Guidelines cannot provide an impairment rating for all impairments… In situations where impairment ratings are not provided, these Guidelines suggest that medical practitioners use clinical judgment, comparing measurable impairment resulting from the unlisted condition to measurable impairment resulting from similar conditions with similar impairment of function in performing activities of daily living.’ The assessor must stay within the body part/region when using analogy.The assessor’s judgment, based upon experience, training, skill, thoroughness in clinical evaluation, and ability to apply the Guidelines criteria as intended, will enable an appropriate and reproducible assessment to be made of clinical impairment.

1.24 - 1.25 Activities of daily living

1.24 Many tables in AMA5 (eg in the spine section) give class values for particular impairments, with a range of possible impairment values in each class. Commonly, the tables require the assessor to consider the impact of the injury or illness on activities of daily living (ADL) in determining the precise impairment value. The ADL which should be considered, if relevant, are listed in AMA5 Table 1–2 (p 4). The impact of the injury on ADL is not considered in assessments of the upper or lower extremities.

1.25 The assessment of the impact of the injury or condition on ADL should be verified, wherever possible, by reference to objective assessments – for example, physiotherapist or occupational therapist functional assessments and other medical reports.

1.26 Rounding

1.26 Occasionally the methods of the Guidelines will result in an impairment value which is not a whole number (eg an assessment of peripheral nerve impairment in the upper extremity). All such values must be rounded to the nearest whole number before moving from one degree of impairment to the next (eg from finger impairment to hand impairment, or from hand impairment to upper extremity impairment) or from a regional impairment to a WPI. Figures should also be rounded before using the combination tables. This will ensure that the final WPI will always be a whole number. The usual mathematical convention is followed where rounding occurs – values less than 0.5 are rounded down to the nearest whole number and values of 0.5 and above are rounded up to the next whole number. The method of calculating levels of binaural hearing loss is shown in Hearing impairment, paragraph 9.15, Chapter 9 in the Guidelines.

1.27 - 1.28 Deductions for pre-existing condition or injuries

1.27 The degree of permanent impairment resulting from pre-existing impairments should not be included in the final calculation of permanent impairment if those impairments are not related to the compensable injury. The assessor needs to take account of all available evidence to calculate the degree of permanent impairment that pre-existed the injury.

1.28 In assessing the degree of permanent impairment resulting from the compensable injury/condition, the assessor is to indicate the degree of impairment due to any previous injury, pre-existing condition or abnormality. This proportion is known as ‘the deductible proportion’ and should be deducted from the degree of permanent impairment determined by the assessor. For the injury being assessed, the deduction is 1/10th of the assessed impairment, unless that is at odds with the available evidence.

1.29 - 1.30 Adjustment for the effects of orthoses and protheses

1.29 Assessments of permanent impairment are to be conducted without assistive devices, except where these cannot be removed. The assessor will need to make an estimate as to what is the degree of impairment without such a device, if it cannot be removed for examination purposes. Further details may be obtained in the relevant sections of the Guidelines.

1.30 Impairment of vision should be measured with the claimant wearing their prescribed corrective spectacles and/or contact lenses, if this was usual for them before the injury. If, as a result of the injury, the claimant has been prescribed corrective spectacles and/or contact lenses for the first time, or different spectacles and/or contact lenses than those prescribed pre-injury, the difference should be accounted for in the assessment of permanent impairment.

1.31 - 1.33 Adjustment for the effects of treatment

1.31 In circumstances where the treatment of a condition leads to a further, secondary impairment, other than a secondary psychological impairment, the assessor should use the appropriate parts of the Guidelines to evaluate the effects of treatment, and use the Combined Values Chart (AMA5, pp 604–06) to arrive at a final percentage of WPI.

1.32 Where the effective long-term treatment of an illness or injury results in apparent substantial or total elimination of the claimant’s permanent impairment, but the claimant is likely to revert to the original degree of impairment if treatment is withdrawn, the assessor may increase the percentage of WPI by 1%, 2% or 3%. This percentage should be combined with any other impairment percentage, using the Combined Values Chart. This paragraph does not apply to the use of analgesics or anti-inflammatory medication for pain relief.

1.33 Where a claimant has declined treatment which the assessor believes would be beneficial, the impairment rating should be neither increased nor decreased – see paragraph 1.35 for further details.

1.34 Refusal of treatment

1.34 If the claimant has been offered, but has refused, additional or alternative medical treatment that the assessor considers likely to improve the claimant’s condition, the medical assessor should evaluate the current condition without consideration of potential changes associated with the proposed treatment. The assessor may note the potential for improvement in the claimant’s condition in the evaluation report, and the reasons for refusal by the claimant, but should not adjust the level of impairment on the basis of the claimant’s decision.

1.35 Future deterioration of a condition

1.35 Similarly, if a medical assessor forms the opinion that the claimant’s condition is stable for the next year, but that it may deteriorate in the long term, the assessor should make no allowance for this deterioration.

1.36 Inconsistent presentation

1.36 AMA5 (p 19) states:

Consistency tests are designed to ensure reproducibility and greater accuracy. These measurements, such as one that checks the individual’s range of motion are good but imperfect indicators of people’s efforts. The assessor must use their entire range of clinical skill and judgment when assessing whether or not the measurements or test results are plausible and consistent with the impairment being evaluated. If, in spite of an observation or test result, the medical evidence appears insufficient to verify that an impairment of a certain magnitude exists, the assessor may modify the impairment rating accordingly and then describe and explain the reason for the modification in writing.

This paragraph applies to inconsistent presentation only.

1.37 - 1.39 Ordering of additional investigations

1.37 As a general principle, the assessor should not order additional radiographic or other investigations purely for the purpose of conducting an assessment of permanent impairment.

1.38 However, if the investigations previously undertaken are not as required by the Guidelines, or are inadequate for a proper assessment to be made, the medical assessor should consider the value of proceeding with the evaluation of permanent impairment without adequate investigations.

1.39 In circumstances where the assessor considers that further investigation is essential for a comprehensive evaluation to be undertaken, and deferral of the evaluation would considerably inconvenience the claimant (eg when the claimant has travelled from a country region specifically for the assessment), the assessor may proceed to order the appropriate investigations provided that there is no undue risk to the claimant. The approval of the referring body for the additional investigation will be required to ensure that the costs of the test are met promptly.

Part 3 - Administrative process

1.40 - 1.41 Medical assessors

1.40 An assessor will be a registered medical practitioner recognised as a medical specialist.

The assessor will have qualifications, training and experience relevant to the body system being assessed. The assessor will have successfully completed requisite training in using the Guidelines for each body system they intend on assessing. They will be listed as a trained assessor of permanent impairment for each relevant body system(s) on the SIRA website.

1.41 An assessor may be one of the claimant’s treating practitioners or an assessor engaged to conduct an assessment for the purposes of determining the degree of permanent impairment.

1.42 - 1.45 Information required for assessments

1.42 Information for claimants regarding independent medical examinations and assessments of permanent impairment should be supplied by the referring body when advising of the appointment details.

1.43 On referral, the medical assessor should be provided with all relevant medical and allied health information, including results of all clinical investigations related to the injury/condition in question.

1.44 Most importantly, assessors must have available to them all information about the onset, subsequent treatment, relevant diagnostic tests, and functional assessments of the person claiming a permanent impairment. The absence of required information could result in an assessment being discontinued or deferred. AMA5 Chapter 1, Section 1.5 (p 10) applies to the conduct of assessments and expands on this concept.

1.45 The Guidelines and AMA5 indicate the information and investigations required to arrive at a diagnosis and to measure permanent impairment. Assessors must apply the approach outlined in the Guidelines.

Referrers must consult this publication to gain an understanding of the information that should be provided to the assessor in order to conduct a comprehensive evaluation of impairment.

1.46 - 1.51 Reports

1.46 A report of the evaluation of permanent impairment should be accurate, comprehensive and fair. It should clearly address the question(s) being asked of the assessor. In general, the assessor will be requested to address issues of:

  • current clinical status, including the basis for determining maximum medical improvement
  • the degree of permanent impairment that results from the injury/condition, and
  • the proportion of permanent impairment due to any previous injury, pre-existing condition or abnormality, if applicable.

1.47 The report should contain factual information based on all available medical information and results of investigations, the assessor’s own history-taking and clinical examination. The other reports or investigations that are relied upon in arriving at an opinion should be appropriately referenced in the assessor’s report.

1.48 As the Guidelines are to be used to assess permanent impairment, the report of the evaluation should provide a rationale consistent with the methodology and content of the Guidelines. It should include a comparison of the key findings of the evaluation with the impairment criteria in the Guidelines. If the evaluation was conducted in the absence of any pertinent data or information, the assessor should indicate how the impairment rating was determined with limited data.

1.49 The assessed degree of impairment is to be expressed as a percentage of WPI.

1.50 The report should include a conclusion of the assessor, including the final percentage of WPI. This is to be included as the final paragraph in the body of the report, and not as a separate report or appendix. The report must include a copy of all calculations and a summary table. A template reporting format is provided in the WorkCover Guidelines on independent medical examinations and reports.

1.51 Reports are to be provided within 10 working days of the assessment being completed, or as agreed between the referrer and the assessor.

1.52 - 1.53 Quality assurance

1.52 The degree of permanent impairment that results from the injury must be determined using the tables, graphs and methodology given in the Guidelines, as presented in the training in the use of the Guidelines and the applicable legislation. If it is not clear that a report has been completed in accordance with the Guidelines, clarification may be sought from the assessor who prepared the report.

1.53 An assessor who is identified as frequently providing reports that are not in accord with the Guidelines, or not complying with other service standards as set by SIRA, may be subject to SIRA performance monitoring procedures and be asked to show cause as to why their name should not be removed from the list of trained assessors on the SIRA website.

1.54 - 1.57 Code of conduct

1.54 Assessors are referred to the Medical Board of Australia’s Good Medical Practice: A Code of Conduct for Doctors in Australia, 8.7 Medico-legal, insurance and other assessments.

1.55 Assessors are reminded that they have an obligation to act in an ethical, professional and considerate manner when examining a claimant for the determination of permanent impairment.

1.56 Effective communication is vital to ensure that the claimant is well informed and able to maximally cooperate in the process. Assessors should:

  • ensure that the claimant understands who the assessor is and the assessor’s role in the evaluation
  • ensure that the claimant understands how the evaluation will proceed
  • take reasonable steps to preserve the privacy and modesty of the claimant during the evaluation
  • not provide any opinion to the claimant about their claim.

1.57 Complaints received in relation to the behaviour of an assessor during an evaluation will be managed in accordance with the process outlined in theWorkCover Guidelines on independent medical examinations and reports and SIRA performance monitoring procedures.

1.58 Disputes over the assessed degree of permanent impairment

1.58 Where there is a discrepancy or inconsistency between medical reports that cannot be resolved between the parties, the Workers Compensation Commission has the jurisdiction to determine disputes about assessed degree of permanent impairment.


* As of 1 September 2015, the workers compensation insurance regulatory functions of WorkCover NSW have been assumed by the State Insurance Regulatory Authority (SIRA).