Hazelbrook: when you might need an injury compensation lawyer

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.

Whole person impairment, or WPI, is a percentage that describes how much a lasting injury affects the body as a whole. It isn't a measure of pain, and it isn't a measure of what you've lost. It's a medical assessment made under set guidelines once an injury has stabilised. In a CTP claim, WPI matters mainly for damages: non-economic loss is only available where WPI is more than 10%.

An assessment above 10% opens damages for non-economic loss and changes some timing rules as well. But many people with genuine, lasting injuries are assessed at 10% or less. That doesn't mean the injury isn't real, or that there is no damages claim. Economic loss, such as lost earning capacity, can still be claimed where the other conditions are met.

Serious physical injuries often bring a psychological toll: sleeplessness, anxiety, depression or trauma symptoms. These can be part of your claim in their own right. Make sure how you're coping is on the record, not just your physical injuries. Whether a psychological injury is threshold or more is a medical and legal question, and the insurer's decision on it can be reviewed.

There's usually no single moment when WPI is measured. Opinions may come from reports you obtain, from examinations the insurer arranges, and, where the two sides disagree, from a medical assessment through the Personal Injury Commission. Timing matters, because injuries can improve or worsen for months. A lawyer can advise whether an assessment is premature before you rely on it.

• 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

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 threshold line is a legal line drawn around medical facts. The diagnosis describes the injury; the scheme's definition decides which side it falls on. Sprains, strains and whiplash without nerve findings usually sit on the threshold side. Confirmed nerve damage, a tear, a fracture or a brain injury generally takes an injury beyond it. The insurer makes the call, and you can challenge it.

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.

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
• A diary of how the injury affects daily life
• Records of how the injury affects your work