Two stages catch out solicitors who instruct expert witnesses infrequently: Part 35 questions after the report lands, and the joint statement once a second expert is involved. Neither stage should be a surprise, and both have a fairly predictable shape once you have been through them a few times. A joint statement only arises where two experts have been instructed separately; where a single joint expert has been appointed instead, there is no second report to reconcile, though Part 35 questions can still be put to an SJE in the usual way.
Part 35 questions
Under CPR 35.6, a party may put written questions to an expert, including a single joint expert, for the purpose of clarifying the report. Questions must be proportionate, put once only unless the court permits otherwise, and are normally limited to clarification rather than an attempt to reopen or expand the substance of the opinion. In practice this means questions should not be a backdoor way of asking the expert to address new issues that were never part of the original instruction.
The court will usually have set a deadline for questions and for the expert's answers in the case management directions. Where no deadline has been set, questions should still be sent promptly after the report is received, since late questions create a real risk that the answers will not be available in time for the next procedural step. I treat Part 35 answers with the same rigour as the original report: each answer goes back to the records and reasoning behind it, and I will say plainly if a question goes beyond what was properly part of the original instruction.
A report that generates extensive Part 35 questions is not necessarily a poor report, complex breach of duty and causation issues attract genuine queries, but a report that is unclear about its own assumptions, or that blurs fact and opinion, tends to generate more questions than one that sets this out properly from the outset.
Joint statements between experts
Where both parties have instructed their own expert, the court will usually direct a discussion between the experts followed by a joint statement under CPR 35.12, recording the areas of agreement and disagreement and the reasons for any disagreement. The purpose is to narrow the issues before trial, not to produce a compromise opinion. An expert should not change a properly reasoned view simply to reach agreement.
The discussion itself is usually conducted by telephone or video conference, sometimes with an agreed agenda prepared in advance by the instructing solicitors, and occasionally with solicitors present by direction of the court, though more commonly the experts discuss matters alone. I find a clear agenda makes a significant difference to how productive the discussion is: where the questions are specific and grounded in the actual point of dispute, it is usually possible to identify quickly whether there is a genuine difference of clinical opinion or simply a difference in the facts each expert has been asked to assume.
Once a joint statement is signed, it stands as the evidence of what is agreed and what remains in dispute, and forms the basis for how the trial addresses the expert evidence. Solicitors should expect the statement to be drafted promptly after the discussion while the reasoning is fresh, and should build that into the case timetable rather than treating it as an afterthought once the discussion has taken place.