This is an important question as anyone who is involved in "expert witnessing" knows. The legal establishment has recognised this for some time. First and foremost an experet witness is there to help the court by explaining the technicalities (science) of the case - not to advocate the cause of their client. Unfortunately too many "experts" seem to forget this. To try and overcome this, several bodies, some of them commercial, have set up training courses in how to become an "expert witness".

In the UK, a number of lawyers and forensic experts across the disciplines, established the Academy of Experts. In order to become a member it is necessary to undergo appropriate training and to understand what is proper, and what it is not proper, for anyone called upon to be an "expert witness" in court, to do.

There is a danger with such a practice of producing expert or professional "expert witnesses" who are not really expert in the subject they profess to know about and in which they are respected by their peers. In medicine this can easily be checked by looking up their publication record in PubMed - I do not think it is always as easy in other desciplines.In the UK The Ministry of Justice, which determines the levels of fees it is prepared to pay "expert witnesses" for cases funded by legal aid, does recognise that some "experts" are more expert than others and can be paid more - but doesn't say how they should be defined. I think it would be a retrograde step for there to be a requirement of genuine experts in a field, who may only be called up only very occasionally to give expert advice to assist the court to be state registered but the present pretty haphazard way of selecting experts to appear and advise the court needs serious re-examination. Vincent Marks

I absolutely agree with Steven; it is I believe essential to distinguish an "expert" witness who has an international reputation from a "professional" expert ie one who is a practitioner in the field who is competent but not a recognised authority.

I am currently a member of a pan European expert witness organisation advising the European Commission on the regulation of experts across the EU. The general observation is that experts operating in European Courts will have some formal training in the role of the expert witness and be registered as an expert in at least one of the EU States. This is not the same as being a 'professional expert' and I agree with all that such a 'vocation/profession' would be to some extent a contradiction in terms.

The idea is that experts operating in EU state courts are verified as expert and operate to a code of ethics while giving evidence. I have seen some utterly peculiar behaviour from experts in trials both in the civil and criminal courts and the status of some has often been questionable.

Clearly some means of determining expertise is desirable, and yes there are certainly cases where this has been questionable. The problem with establishing expertise is that judiciary and legal practitioners have no knowledge of the area in question, so are not equipped to evaluate the "expert's" answers. For that reason, I welcome a system of accreditation. However, I do wonder how this would play out in adversarial versus inquisitorial systems, where the motivation to enlist an expert can be very different.

We should to difference type of "decision making": deterministic - statistic - intuitive - legal - nonlegal. When I am forensic engineering expert - as a State investigator of occupational injuring - I am taking all forensic evidences with usage exact scientic method crimi tracing - including Geometry, Radiology, Biomechanics, etc. - All my evidences could be allways scientic reviewed on likehood Crimi Policy Laboratory. For example: when I have argumented by Court: There are absency of Preliminary processing Planning of surgery THA, allways there should be mandatory defined preliminary planned positional placeing the implants (the spice Stem in femural axis in coordinates Xi, Yi, Zi) adequated to my skeletal individual conditions by Directive 93/42/EEC Medical Devices including with context with describing in product instruction of set THA by "CE" marking. It is clear NONLEGAL MEDICAL WORKING since the begin. When the Court expert for Orthopaedy didn´t refute such medical mistake - he said "all was Lege artis realised" , then his "opinion about legality of medical working is comic nonsense!" I have been immediately claimed the forensic Physicians so as Judge processing - because Physicians was ignoring my engineering crimi evidences, I asked full annulating Court processing by the ministry of Justice Czech Republic - when I has been informed all participants on this aspects befopre beginning Court dealing by written - the judge didn´t take me possibility to exploatation my evidences in duration of Court dealing - it´s absolute contrary Constitutional Human Rights for Court processing! Then I willcome all forensic expert on my Profile on LinkedIN, there are my Court case of Regional Court Prague No 36 C 181/2009 in detail described. Exact evidences must be allways preferenced by evaluating of evidences - against "physicians intuitive hypotheses" only.

Steven. I absolutely agree with you " that it is virtually impossible to be an expert in more than one very narrow area "

Marks. The tie-up between publication record and expertise should continuously be examined, given the increasing number of retractions, conflict of interest cases and fraudulent published research.