This can be achieved through the use of expert evidence.

Employers can engage an appropriate expert to produce a report on a worker’s injury, including what caused or aggravated it. The expert will review any instructions and background materials provided by the employer alongside its assessment of the worker. It is a lawful and reasonable direction that the worker attend the appointment with the expert for this assessment.

Prior to the assessment, the employer must provide the expert with relevant materials (excluding any WorkCover documentation) including a description of worker’s role and a copy of their position description, details of the injury and copies of any relevant medical certificates supplied by the worker and, if applicable, details of any return to work and the nature of any light duties/hours.

It is up to the employer to provide the expert with explicit instructions around what questions it would like the expert to answer, and these must be tailored according to the claim. For example, if the claim is the worker suffered an aggravation of an injury at work, opinions should be sought around the other potential causes for the aggravation.

In Tassal Operations Pty Ltd v Lese [2021] TASSC 22, an employer was unable to dispute liability for the aggravation of its worker’s underlying disease, as it did not produce sufficient evidence to suggest there were other possible causes of the aggravation which might qualify as the major or most significant factor.

The employer’s insurer engaged an expert to report on the worker’s disease and its aggravation. It provided the expert with medical certificates and reports produced by the worker’s general practitioner. The expert reviewed these materials and met with the worker to interview and examine him. He concluded the worker’s disease was aggravated from an incident at work.

The employer’s insurer then provided the expert with records suggesting the history provided by the worker differed significantly from that which had been recorded by the employer, and sought a further report. The expert retracted his earlier conclusion and noted he was uncertain as to whether the aggravation was caused by the worker’s employment.

The employer had not asked for any opinions around other possible causes for the aggravation, and instead sought to rely on the experts uncertainty to dispute liability and suggest it could not be proven that the aggravation was caused by the worker’s employment. However, the uncertainties contained within the second report caused it to be viewed with very little weight, leaving the only acceptable evidence produced on this point being the first report which concluded the worker’s disease was aggravated from an incident at work.

Lessons

• Where there are a variety of potential causes for a condition, an employer must show a reasonably arguable case concerning liability by providing evidence of plausible potential causes that are inconsistent with liability.
• If sufficient materials are not provided to an expert, the expert will have no choice but to accept the worker’s evidence on face value which would obviously not identify deficiencies or weaknesses in the claim and therefore will not be useful for an employer in disputing liability.
• If an employer’s instructions to an expert are not explicit enough, there is risk that the expert report will contain uncertainties and not be afforded much weight in identifying deficiencies or weaknesses in the claim to dispute liability.