Injury compensation lawyer Waitara: impairment explained

Two measurements do most of the work when an injury is serious. One is the threshold line, which separates soft tissue and some psychological injuries from everything else. The other is whole person impairment, a percentage that describes lasting impairment. Between them, they affect how long statutory benefits can run and what a damages claim, if you have one, can include.

A serious injury can change more than the next few months of work. It can limit the kind of work you can do for years, or permanently. In a damages claim, that is called loss of future earning capacity, and it can be a significant part of a serious injury claim. It generally needs medical evidence, your work history and sometimes vocational experts.

The definition works by exclusion. An injury is generally threshold if it is soft tissue damage with no nerve damage and no torn tendon, ligament, meniscus or cartilage, whether the tear is complete or not, or if it is a psychological injury the scheme classes as threshold. Injuries outside that description, such as fractures, torn ligaments or brain injuries, are generally more than threshold.

The line also decides whether common law damages are open. With only a threshold injury, they generally aren't. With a more serious injury, you may be able to claim damages if another driver was at fault and you weren't mostly at fault. That is why a threshold decision is often the most important decision the insurer makes about a serious injury.

Impairment is generally assessed once an injury has stabilised, meaning it's unlikely to change much from here. Assessing too early can understate a serious injury. The insurer may arrange an assessment, you may obtain your own reports, and if the insurer and you disagree about the degree of impairment, the Personal Injury Commission can carry out a medical assessment.

• Whether every injured body part is included
• Changes in your condition since the last report
• Whether you disagree with the result, and the deadline to say so

WPI turns a lasting injury into a percentage. An assessor examines you and rates the impairment under the guidelines that apply to motor accident claims. The number doesn't reflect how hard your life has become; it reflects measurable impairment. Even so, it can decide important questions, especially whether damages for pain and suffering are possible.

Because so much can turn on a few percentage points, WPI assessments are often contested. Reports prepared for you, for the insurer and, if there's a dispute, by a medical assessor through the Personal Injury Commission may reach different figures. Keep every report, and get advice before accepting an assessment you think is wrong.

A crash can cause psychological injury as well as physical injury, and sometimes instead of it. Some psychological injuries are classed as threshold injuries; others are not, depending on the diagnosis. Anxiety, low mood, flashbacks or fear of driving are worth having recorded early, so the injury is properly identified in the claim rather than surfacing months later.

The most persuasive serious injury claims usually have consistent evidence: the same injuries described the same way from the first record to the last, with no unexplained gaps. That consistency comes from giving the full story every time you describe the injury. If a report leaves something out, raise it rather than letting it pass, and keep a note of when you did.

• Any reports prepared for the claim
• Every Certificate of Fitness, in order
• Records of how the injury affects your work
• Any impairment assessment, and your response to it