Where several accidents affect the same body region or psychological condition, the expert must establish what changed after each event. The task is not to divide symptoms mechanically between dates. It is to reconstruct the claimant’s condition before and after every accident and explain what can be attributed reliably to each one.
Start with a separate chronology.
Multiple-accident cases become confused when the history is written as one continuous narrative. The expert should create a chronology showing the date and mechanism of each accident, the symptoms reported afterwards, treatment, work absence, functional change and recovery before the next event. Consultations between accidents may matter more than records created immediately after them.
A clear chronology may show complete recovery after the first event, continuing symptoms when the second occurred or a change in the presentation. It may also reveal a long period without treatment requiring explanation.
Records should be compared with the claimant’s account rather than treated as infallible. Clinical notes may omit minor symptoms. Equally, a claimant may remember several events as one prolonged period of illness. Material differences should be identified and put to the claimant neutrally.
Establish a baseline before every accident.
A pre-accident baseline is required for more than the first event. Before considering the second accident, the expert should establish the claimant’s condition immediately beforehand. Had the earlier symptoms resolved? Were they improving, stable or deteriorating? Was the claimant working normally, taking medication or receiving treatment?
This produces a sequence of baselines. The claimant may have been symptom-free before the first accident, partly recovered before the second and significantly restricted before the third.
A diagnosis alone does not establish the baseline. Two records may use the term “neck pain”, while one describes occasional stiffness and the other daily pain preventing work. Function, treatment and severity provide the necessary context.
Do not assume the latest accident caused everything.
The most recent accident often receives the greatest attention because it is the subject of the instruction. That does not make it responsible for all continuing symptoms.
If the claimant had persistent pain immediately before the latest event, the expert must identify the additional change. The later accident may have caused a temporary flare-up, a new injury, an acceleration of an existing condition or no material alteration. The reverse mistake also occurs. An expert may attribute symptoms entirely to the first accident because it started the sequence. A later event may introduce different symptoms or a marked increase in disability.
The question is what difference each event probably made.
Look for changes in the clinical pattern.
Different injuries can affect the same anatomical area. An earlier accident may have caused muscular neck pain that was improving. A later collision may produce arm symptoms or altered sensation requiring separate assessment. Similarly, a claimant with earlier general anxiety may develop specific travel fear after a later road accident.
The expert should compare symptom location, quality, severity and function after each event. New features may support a distinct injury. An increase in the same symptoms may indicate aggravation. No documented or reported change may weaken the suggestion that the later event caused additional harm.
A symptom-free interval can be persuasive, but it is not essential. A person can sustain a further injury before recovering from the first. Incomplete recovery makes attribution harder, not impossible.
Avoid false precision.
Solicitors may ask the expert to apportion the claimant’s condition between several accidents. Sometimes a broad clinical division can be made. An expert may conclude that the first accident caused symptoms lasting six months and the second prolonged recovery. In other cases, the effects overlap so closely that a percentage division has no proper medical foundation.
The expert should not state that one accident caused 60% of the symptoms and another caused 40% merely because a numerical answer has been requested. A reasoned description is more defensible: the first accident caused the original condition, recovery was incomplete, and the later accident produced a temporary worsening.
Practice Direction 35 requires experts to consider all material facts, including those that detract from their opinions, and to make clear when the available information does not permit a definite conclusion. The GMC likewise requires expert evidence to be accurate, objective and clear about conflicting or insufficient information Uncertainty should be explained rather than converted into arithmetic.
Consider recovery between events.
Treatment records may show whether the claimant was recovering before the next accident.
Reduced medication, discharge from physiotherapy, return to work and resumed activities can support improvement. Continuing referrals and unchanged restrictions may indicate that the earlier injury remained active. Attendance alone does not prove severity. A claimant may continue treatment after substantial recovery, while another may remain symptomatic without seeking help. The expert should examine response to treatment and actual function.
Where a later accident interrupts rehabilitation, the expert should consider whether it delayed recovery or produced a new condition requiring different treatment.
Psychological effects need the same discipline.
Multiple accidents can produce overlapping anxiety, travel fear or trauma-related symptoms. The expert should ask which event is recalled intrusively, which situations are avoided and whether the claimant had resumed driving before the later collision. Symptoms may accumulate, but they should not automatically be attributed equally to every event.
Previous vulnerability, unrelated life events and continuing pain may also contribute. Alternative explanations should be addressed rather than hidden within one broad diagnosis.
A claimant may have recovered physically from the first accident while continuing to experience travel anxiety. A later collision may aggravate that anxiety even where it causes little additional physical injury. The expert should therefore assess physical and psychological consequences separately before considering how they interact.
The final opinion should show its reasoning.
A useful report should state the condition before each accident, the immediate effect of each event, the recovery achieved before the next one and the claimant’s present position. It should distinguish new injury from aggravation, acceleration and recurrence. Where the records are incomplete or factual accounts differ, the expert may need to provide alternative opinions. For example, one opinion may apply if the claimant had recovered before the later accident and another if continuing symptoms are accepted.
Further evidence should be recommended only where it is likely to resolve a material question. A specialist report should not be obtained merely because the history is complicated. The unresolved issue and the appropriate discipline should be identified clearly. Multiple accidents do not require a perfect division of every symptom. They require a disciplined chronology and an honest account of what the evidence supports.
The safest conclusion is not always that one accident caused everything. It is the explanation that best describes how the claimant’s condition changed, event by event
