1.2.6 Fitness-to-work and disability evaluation

The terms “unfit”, “disabled” and “impairment”:


The term medically “unfit” refers to the failure to meet the specific inherent requirements of an occupation due to the presence of a medical condition that is an exclusion for the relevant occupation, or due to a lack in the capacity (physical or mental) to perform the work, to the required standard.

Note that a person may be “unfit”, but not “disabled”! An example of this is a small and lightly built person who applies for a job that entails heavy manual labour.

Point to Ponder:

The degree to which a person is unsuitable to work in a particular occupation varies according to circumstances. For example, a job applicant who fails to meet a minimum statutory requirement, or for whom the risks of the occupation are unavoidable and life-threatening, the degree of unsuitability would be regarded as a non-negotiable. The medical conditions that lead to the failure to meet these requirements would be regarded as “absolute exclusions”.

An example of an “absolute exclusion” would be the presence of blindness, in a company driver of a vehicle carrying hazardous substances, on the national roads.

It is logical to conclude that there are always many medical conditions that are only exclusions when they are present with other factors. On their own, they may pose an acceptable degree of risk, with or without certain “restrictions”. These restrictions could be on the working conditions, or that the employee’s health condition remains satisfactory. These medical conditions are known as “relative exclusions”.

An example of a “relative exclusion” would be as follows. The occupation entails potential exposure to lung irritants, such as chlorine or ammonia. Lung protection is reliant upon adequate ventilation or by means of PPE (respirators, etc). Mild asthma could be regarded as a relative exclusion, with the proviso (“restriction”) that:

o        lung function be monitored regularly, and that there be no significant decline of measured function (health condition)

o        the employee is not exposed to levels of lung irritants that exceed the statutory limits (working condition)


The term “impairment” refers to specific deviations from the functional capabilities that would be expected of an average healthy individual. Hence losses of hearing or lung function, or a joint which loses a certain degree of its range of motion, are all references to impairments. These impairments are NOT necessarily disabilities, nor do they render a person automatically “unfit”. The degree to which the impairment becomes a disability is determined by the degree to which the impairment impacts on a variety of issues, such as the ability to earn an income, or to function independently in society (see later in this section).

An example of an impairment that does not translate automatically into a disability is that of hearing loss. The formula that is used widely for calculating disability for hearing loss (and, therefore, compensation), places a much higher weighting on the frequencies that affect speech, than those in the very high frequencies. Hence the impairment can be substantial, with a calculated disability of zero.

The difference between impairment and disability is particularly important. It is important to remember that the members of the medical evaluation team should only focus on the level of impairment and should try to avoid making inferences regarding the degree of disability, which should be left to the insurer.


The term “disability” refers to an impairment, which prevents the person from accomplishing certain tasks, or from performing an occupation, thereby impacting on his/her ability to live a normal life, or to earn an income. The calculation of disability is therefore complex and is determined by legal, ethical and actuarial influences. The process of converting impairment to disability is important to the insurance industry, and also in the awarding of damages in legal claims.

The Compensation Commissioner has established tables that enable the conversion from impairment to disability. Examples include the tables for loss of hearing and loss of lung function. Interestingly, the COIDA uses the term “disablement”, rather than the more widely used term, “disability”.

Note that a person with a disability is not necessarily unfit for the job which they hold. An example of this is an employee who loses the tip of a finger in an accident (thereby incurring a disability), but who is still perfectly able to continue in his/her job. Hence the disability only renders the person “unfit”, if it changes their health status in a way that becomes an “exclusion” in terms of the job’s “inherent requirements” (see above).

When one refers to an employee being impaired or disabled, there are two important descriptors that should be used to define the problem completely. These are:

1 Extent

2 Duration

Extent of disability (impairment):

  • Total Disability

This refers to a disability, which renders the affected person totally unable to perform any form of recognised occupation.

  • Partial Disability

This refers to a disability, which interferes specifically with tasks or activities that render the affected person unable to perform certain occupations only.

Duration of disability (impairment):

  • Temporary Disability

This refers to a disability, which affects a person for a discreet and temporary period of time. This may be brief, such as somebody with an injury, which recovers within a few days to weeks, or may be long, such as a person with an illness or injury with a prolonged convalescence (tuberculosis, major injuries).

  • Permanent Disability

This refers to a disability, which affects the person permanently, or which is untreatable. A typical example of this would be noise-induced hearing loss, spinal injuries, silicosis and asbestosis. To the Compensation Commissioner, “permanence” also has an administrative definition of “permanent” – conditions which have a temporary disability for longer than two years are regarded as “permanent”. This is in order to prevent protracted case dockets. This is not so in the private insurance industry, which often continues to review even long-term cases every one to two years, in order to ascertain whether or not the affected party has recovered sufficiently to reverse the status of “disabled”.

Hence the permutations of these circumstances are as follows:

  • Temporary partial disability (TPD): this refers to those employees on “light duty” (able to perform alternative, less demanding work). It should be remembered that the practice of making available light duty is not universally practiced in companies – this is something negotiated between the company and the employee.
  • Temporary total disability (TTD): this is the situation for employees on sick leave or accident leave. They are totally unable to continue in their usual occupation and are sent home (or to hospital) to recover.
  • Permanent partial disability (PPD): this applies in the same manner as temporary partial disability, but the disability is permanent. That is to say it is not medically treatable.
  • Permanent total disability (PTD): this applies in the same manner as temporary total disability, but the disability is permanent. That is to say it is not medically treatable.


From the above it is clear that a central theme in the concept of “fitness to work” is that of required minimum “standards of fitness”, or “inherent requirements”. These minimum standards of fitness can be regarded as the factors that are required for specific occupations and are determined by the liability & exposure risk profiles of those occupations. These minimum standards need to be established in a way that is fair and rationally defendable and expressed in a way that is measurable, to ensure consistent application.

The Occupational Health and Safety Act requires people in occupations that entail potential exposure to certain hazards (such as noise, lead, hazardous chemical substances and hazardous biological agents) to be subjected to medical screening, to determine their fitness to work in the said occupations.