Injury compensation lawyer Shalvey: impairment explained

In everyday speech, a serious injury is one that hurts a lot or takes a long time to heal. The CTP scheme uses narrower tests. The first is whether the injury is more than a threshold injury. The second, for some kinds of compensation, is how much permanent impairment it leaves, measured as whole person impairment. Pain matters to you, but the scheme looks at diagnosis and lasting effect.

There's usually no single moment when WPI is measured. Opinions may come from treating doctors, from doctors 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 the injury has stabilised
• How complete and current your medical records are
• Scans or tests your doctors have ordered

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 raising with your GP early, both for your own sake and so the injury is recorded and properly diagnosed.

Earning capacity compares what you could have earned without the injury with what you can realistically earn now. For a tradesperson with a damaged shoulder, or an office worker with a brain injury, that gap can be large and long-lasting. Record every change to your working life: hours, duties, roles you can no longer do. Those facts sit alongside the medical evidence.

The threshold line is a medical line drawn by legal rules. Your doctor diagnoses 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.

People are often surprised by how technical WPI is. It is assessed under guidelines that rate specific impairments, such as lost movement in a joint, and express the result as a whole-body percentage. More than 10% is the key line in CTP claims, because damages for non-economic loss, meaning pain and suffering, are only available above it. Loss of earnings doesn't need that level.

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.

Serious injury claims rest on medical evidence gathered over time: hospital records, imaging, operation reports, specialist opinions, and treating doctors' notes that track your progress. Your own records add the human detail. Start collecting early, keep everything in date order, and make sure each doctor knows about all your injuries, not just the one they're treating.

• Every Certificate of Fitness, in order
• Reports from a treating psychologist or psychiatrist, if any
• Records of how the injury affects your work
• Any impairment assessment, and your response to it