The terms impairment and disability are often interchanged, but
in fact their meanings differ substantially.
While both concepts are about illness and injury, one of the key
differences is impairment should reflect an objective assessment
and disability is a more subjective determination.
Impairment is more about a medical model, whereas disability has
more to do with a social model involving interaction with the
person's environment and community.
Psychiatrist Jill Reddan, a current member of our General Medical
Assessment Tribunal, agrees there can be a significant level of
confusion about the difference between impairment and
'I think there can be confusion not just within the medical
community but also the general community,' Dr Reddan says.
'It's important to understand impairment is an objective construct
defined as 'a loss, loss of use, or derangement of any body part,
organ system or organ function'. 1
'Disability is evaluated by non-medical means and is defined as 'an
alteration of an individual's capacity to meet personal, social or
occupational demands because of an impairment'.2
Dr Reddan explains that sometimes an individual who has sustained
an injury may feel confused that an impairment rating assigned by a
medical practitioner or a tribunal does not adequately reflect the
full impact upon his or her life of the injury.
'This is because an impairment rating cannot take into account all
of the unique implications of an injury to the individual. There is
no way of rating disability and the very same injury can have very
different implications for different individuals'.
'Impairment is a structured and objective-based assessment, whereas
disability determination takes into account what the loss means to
the individual,' Dr Reddan explains.
Under the Queensland workers' compensation scheme, a medical
practitioner may be asked by an insurer to assess a worker's injury
to decide if the injury has resulted in a degree of permanent
impairment (impairment that is stable and stationary).
Dr Reddan explains the assessment of the degree of permanent
impairment, if any, can be a difficult task and it requires
considerable experience in assessing the effects of injury which is
one of the reasons why assessment of impairment is a task for
Dr Reddan says while the definition of impairment concentrates on
loss after an injury it's also important to focus on the level of
function that remains after an injury.
'It has been my personal experience that very often, the higher the
level of impairment the more the injured individual will focus on
the remaining abilities.
'I think it's very important when you are treating someone to focus
on the positives and to help them overcome the problem or the
injury rather than staying fixated on it,' Dr Reddan says.
1,2 Cocchiarella, L & Andersson, G 2000, Guides to the
Evaluation of Permanent Impairment, 5th edn, AMA Press, United
States of America.