As a rule, an expert should not decide whether a claimant is honest. Credibility is a matter for the court, which considers the claimant’s evidence alongside medical records, witness statements, expert opinions and other evidence. The expert’s role is to provide medical analysis, not to determine disputed facts or accuse a witness of dishonesty.
The Court and Expert Have Different Roles.
Under CPR 35.3, an expert’s duty is to help the court on matters within their expertise. That duty overrides any obligation to the party instructing or paying them. Practice Direction 35 also requires expert evidence to be independent, objective and limited to matters within the expert’s professional competence.
The court remains responsible for deciding which factual account should be accepted. An expert who states that a claimant is lying risks stepping beyond medical opinion and assuming the judge’s role. The expert may not have seen all the available evidence or heard the claimant being cross-examined. They may also be unaware of innocent explanations for an apparent discrepancy.
Credibility Is Different From Reliability.
Credibility generally concerns whether a person is telling the truth. Reliability concerns whether their account is accurate and dependable. A claimant may provide inaccurate information without deliberately attempting to mislead. Memory may fade, dates may become confused, symptoms may be described differently at different appointments, and medical notes may not contain a complete history.
The expert may assess whether the claimant’s history is medically reliable enough to support an opinion. That is different from deciding whether the claimant is dishonest.
For example, an expert may state that the reported onset of symptoms is inconsistent with contemporaneous records. They may explain that the alleged degree of disability is difficult to reconcile with examination findings or documented activities. They may also state that a diagnosis depends on the accuracy of the claimant’s account.
These are expert observations about the evidential basis of the opinion. They do not require a conclusion about the claimant’s character or motive.
Experts Should Identify Inconsistencies.
Avoiding a direct credibility judgment does not mean ignoring contradictory evidence. Practice Direction 35 requires experts to consider all material facts, including those that might detract from their opinions. If a claimant denies previous neck symptoms but the records show repeated consultations for neck pain, the discrepancy should be addressed. If the claimant reports being unable to drive but other evidence suggests regular driving, the expert should explore the circumstances and explain whether the information affects diagnosis, causation or prognosis.
The expert should distinguish clearly between the claimant’s account, the documentary evidence and their own clinical findings. Neutral wording is generally more useful than an accusation.
It may be appropriate to state that the accounts cannot be reconciled, that the history is inconsistent or that the reliability of a particular statement is uncertain. It will usually be inappropriate to state that the claimant fabricated the history unless there is a proper specialist basis for that conclusion.
Medical Inconsistency Does Not Prove Dishonesty.
A presentation that is medically unusual is not necessarily fabricated. Symptoms may fluctuate, pain may vary between activities, and a claimant may carry out a task despite discomfort because it is necessary. The absence of abnormal imaging or significant examination findings does not establish that pain is false. Many genuine pain and psychological conditions depend partly on self-report.
Where symptoms appear disproportionate to objective findings, the expert should identify the disparity and consider possible clinical explanations. These may include fear avoidance, deconditioning, chronic pain processes, psychological factors or misunderstanding about physical limitations. The expert should explain what the evidence does and does not establish rather than automatically inferring dishonesty from unexplained inconsistency.
Symptom Exaggeration Requires Careful Language.
There may be cases in which the claimant’s presentation suggests exaggeration, inconsistent effort or unreliable symptom reporting. An appropriately qualified expert may comment on observed behaviour, clinical testing or validity measures within their discipline. The expert should describe precisely what was observed. It may be appropriate to record that performance varied significantly, that test results were internally inconsistent or that the demonstrated restriction could not be anatomically explained.
The report should then explain the medical consequence. The findings may prevent a reliable assessment, reduce confidence in the reported severity or require the prognosis to be qualified. The expert should normally avoid assuming why the inconsistency occurred. Exaggeration can be deliberate, but it may also arise from anxiety, distress, misunderstanding or an attempt to communicate suffering. A finding of dishonesty requires consideration of evidence beyond the medical examination.
Opinions Can Be Conditional.
Where the facts are disputed, the expert does not need to decide which witness is telling the truth. The report may explain how the medical opinion changes depending on the court’s factual findings.
For example, the expert might state that if the claimant’s account of continuous symptoms is accepted, the accident probably caused a prolonged injury. If the records instead demonstrate recovery followed by a later recurrence, the subsequent symptoms may be unlikely to remain accident related.
This approach keeps the expert within their proper role while giving the court useful assistance. It also identifies which factual assumptions are material to diagnosis, causation and prognosis.
Responding to Instructions About Credibility.
Solicitors may ask an expert to comment on credibility where records contain discrepancies or surveillance evidence is available. The expert should usually interpret the request as requiring an assessment of medical consistency and reliability rather than a legal conclusion about honesty. The report should address the evidence, identify contradictions and explain their significance. Expressions such as “the claimant is dishonest,” “the claim is fraudulent” or “the claimant is not credible” should be avoided.
Where the question falls outside the expert’s competence, the expert should say so. The wording of the instructions must not pull the report beyond its proper medical purpose.
The Expert Should Inform, Not Decide.
Experts should not ignore evidence that may affect credibility, but neither should they decide the ultimate question of truthfulness. Their proper role is to assess whether the claimant’s account is consistent with the records, examination findings, recognised clinical patterns and other available information. They should explain how any inconsistency affects the diagnosis, causation opinion or prognosis.
The distinction is important. The expert may identify evidence that assists the court in assessing credibility. The final decision about whether the claimant is truthful belongs to the court.
