AMA Guides and impairment rating are problematic


In most Australian jurisdictions (states and territories), the American Medical Association Guides  (AMA Guides) are the accepted assessment tool for injured workers’ permanent impairment rating. The problem with many AMA Guides (especially the older versions in use such as the AMA Guides 4th ed in Victoria) is that the rated impairment does not take into account the impact the impairment has on the injured worker. What should be measured is disability – that is, how the impairment really affects the injured worker.

The AMA Guide 4th edition (as used in VIC)

guides-evaluation-of-permanent-impairment-fourth-edition-pThe physical guides

Under the Victorian WorkCover legislation physical injuries must be assessed in accordance with the fourth edition of The American Medical Association Guides For The Evaluation Of Permanent Impairment. Although these Guides are now in their six edition, the WorkCover legislation requires the fourth edition to be used, which is 20 years old! The Guides have been modified by the legislation which removes the pain chapter (pain does not rate). The Guides have been the subject of significant criticism because they provide relatively low impairment assessments for musculoskeletal injuries particularly spinal injuries. Indeed, there are good grounds for believing that the scores of the most common industrial injuries were deliberately lowered when the Guides were being developed in the USA. The Guides are highly complex and can provide markedly fluctuating impairment assessments when the same injured worker is assessed by different doctors (IME, Medical Panel etc). These fluctuations, in large measure, are due to the discretion that is provided to medical examiners in respect of choosing the appropriate methodology for some assessments, particularly involving limb function.

The psychological guides

Under the VIC WorkCover legislation a psychological impairment must be assessed in accordance with the Medical Panel Guides for the Evaluation of Psychiatric Impairment which was developed by psychiatric members of the Medical Panel Victoria. The impairment assessment methods consider a number of levels of psychiatric/ psychological functioning including the following:

  • Intelligence – (capacity for understanding).
  • Thinking – (the ability to form or conceive in the mind).
  • Perception – (the brain’s interpretation of internal and external stimuli).
  • Judgement – (ability to assess a given situation and act accordingly).
  • Mood – (emotional tone underlying all behaviours).
  • Behaviour – (behaviour which is disruptive, distressing or aggressive).

Under the VIC WorkCover legislation an assessor is required to ignore, for assessment purposes, any psychological impairment that it is ‘secondary’ to physical injury. This effectively means that where someone is injured in a traumatic incident, the doctor who assesses can take into account that component of the psychological condition which comes from the event itself (e.g. post-traumatic stress disorder – primary psych injury) but must not take into account any psychological condition which is due to having sustained a physical injury (secondary psych injury). For example if you are seriously physically injured and develop major depression as a result from your impairment, disability, pain, loss of joy in life etc, it does not count.

In order to be eligible for an impairment lumpusm payment, in Vitoria, it is necessary to obtain an impairment score of 30% ‘primary’ psychiatric impairment (very rarely achieved). However a primary psychiatric impairment can be combined with a physical impairment for the purposes of reaching the 30% threshold for common law damages claims. (the combination of the 2 is not straight forward, eg if you have 26% WPI for a physical injury and 23% WPI for a primary psych injury, it will add up to 43% (and not 49%) through complex calculations.)

In order to be eligible for a lumpsum for a physical injury the injured worker must have 10% WPI or more. however if you were injured after 3 December 2003 and your injury is to your spine, arms or legs, compensation is payable if you have a 5% whole person impairment or more.

AMA Guides and impairment rating are problematic

These AMA Guides neatly divide up the human body using the concept of whole person impairment (WPI). It is assumed that a 0% WPI is someone who is completely well, yet a person who has 100% WPI is someone who is basically dead. Someone who has 50% WPI is either half dead or half alive, depending how you view it.


These  AMA Guides produce a ‘lovely’ set of figures which are so much loved by workcover insurances.

Generally speaking, the injured worker is allocated a certain amount dollars for each percentage (%) point impairment; and achieving a certain value or level (30% WPI or more in Vic) , according to these Guides, may allow the injured worker to progress with a common law claim.

Impairment means basically the loss of a body part or function. For example, if you loose your left little finger you will receive a 5% whole person impairment (WPI), using the AMA Guides 4th Edition. BUT, the problem is that this WPI rating  is the same whether the injured owner of the lost left little finger is a professional pianist or if that person is a labourer, or an office worker.

Impairment does not take into account the use to which the injured worker might put something. What should be measured (but is not) is in fact disability  – that is, how the impairment really affects the injured worker.

Let’s for example use an injured worker who sustained a moderate to severe back injury. To a labourer – a buggered back can be disastrous. However, to an office (or any sedentary worker) this same back injury can possibly reasonably be accommodated in the workplace. BUT the problem is that, under the AMA Guides 4th Ed,  both the labourer and the office worker with the same injury would receive the same impairment  (WPI) value/rating, even though the disability (or handicap) would be completely different. Same scenario would apply to the concert pianist who lost a finger and an office worker who lost the same finger. The impact of the injury of the concert pianist would be far greater, yet s/he will not rate higher WPI.

Assessing disability (or handicap) and as such the impact an injury has on an injured worker is (arguably) much more difficult to assess than to assess only the impairment. YET the legislators who accept the (outdated) American Medical Association Guides (such as the 4th Ed) have basically ruled that assessing impairment alone—even though it is very inappropriate— should be done and accepted (legislated).

Needless to say that, as a result of the use of the outdated  AMA Guides, many injured workers are being denied compensation even for fairly severe injuries.. Even after some terrible  injuries, some workers may make a reasonable enough recovery (measured mainly by range of movement of body parts, remember crippling pain does not rate)  and have a 0% or almost 0% impairment assessment under these Guides and be denied appropriate compensation for their injuries, pain and suffering etc.

To view wich AMA Guide edition applies to your state, see the Comparison Workers Compensation Arrangements >> and go to page 83 – Table 3.11 : Permanent impairment guides.


Some related articles

[Post by WVC and WCV 3]