Serious injury? Injury compensation lawyer, Greengrove

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 evidence from your doctors, your work history and sometimes vocational experts.

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

• Whether the injury has stabilised
• Whether every injured body part is included
• Scans or tests your doctors have ordered

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.

Getting the classification right early helps. If you have symptoms that could point to nerve involvement or a tear, such as numbness, weakness, locking or a joint giving way, describe them to your doctor. Whether tests are needed is a medical decision. If a diagnosis changes, make sure the insurer has the new evidence, because the classification may need to change with it.

The scheme treats psychological injury seriously, but it still sorts it by diagnosis. A threshold psychological injury is generally handled like a threshold physical one. A more serious diagnosed condition may take the claim beyond the threshold. Because the difference turns on the diagnosis, the opinion of a treating psychiatrist or psychologist can matter a great deal.

WPI turns a lasting injury into a percentage. A doctor examines you and rates the impairment under the assessment 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.

It's easy to overstate the 10% line. You don't need more than 10% WPI to claim damages for past and future loss of earnings; you need an injury that's more than threshold, another driver at fault, and not to have been mostly at fault yourself. The 10% line decides pain and suffering, and it also affects some timing rules for a damages claim.

The most persuasive serious injury claims usually have consistent evidence: the same injuries described the same way, from the hospital to the GP to specialists, with no unexplained gaps in treatment. That consistency comes from telling each doctor the full story and following treatment plans. If a report leaves something out, ask the doctor about it rather than letting it pass.

• Hospital admission and discharge records
• Imaging reports, such as X-ray, CT or MRI, where done
• Operation and specialist reports
• Reports from a treating psychologist or psychiatrist, if any