In most trials in Nigeria, persons are called as witness to prove a particular set of facts in a case. These set of persons are called experts meaning that they are either skilled and knowledgeable at what they do. Some of these experts are medical doctors, scientists, surveyors etc. Most times lawyers cross examining these set of witnesses are faced with certain challenges due to the fact that these experts are more knowledgeable in their field. As a general thing, it is unwise for the cross-examiner to attempt to cope with a specialist in his own field of inquiry. Lengthy cross-examinations along the lines of the expert’s theory are usually disastrous and should rarely be attempted.
However these are ways and tactics a lawyer can use to discredit the evidence and qualifications of the expert.
WHO IS AN EXPERT?
Wikipedia defined an expert as someone who has a prolonged or intense experience through practice and education in a particular field. Informally, an expert is someone widely recognized as a reliable source of technique or skill whose faculty for judging or deciding rightly, justly, or wisely is accorded authority and status by peers or the public in a specific well-distinguished domain. An expert, more generally, is a person with extensive knowledge or ability based on research, experience, or occupation and in a particular area of study.
Blacks Law dictionary 8th edition defined an expert as a person who, through education or experience, has developed skill or knowledge in a particular subject, so that he or she may form an opinion that will assist the fact-finder.
Evicence Act 2011 as ammended recognises and provides for the calling of experts as witnesses during trials.
S. 67 EA provides that the opinion of any person as to the existence or non existence of a fact in issue or relevant to the fact in issue is inadmissible except as provided in sections 68 to 76 of this Act.
S. 68 to 76 provides for the opinion of experts and categories of which they can give their expert Opinon, e.g science, art, custom, etc.
S. 68(1)EA further provides that “when the court has to form an opinion upon a point of foreign law, customary law or custom, or of science or art, or as to identity of handwriting or finger impressions, the opinions upon that point of persons specially skilled in such foreign law, customary law or custom, or science or art, or in questions as to identity of handwriting or finger impressions, are admissible.
(2) Persons so specially skilled as mentioned in sub-section (1) of this section are called experts.
In the case of ANPP V ANOR V. USMAN & ORS (2008) LPELR-CA/K/EP/GOV/51/2007 it was stated that the party calling an expert witness has a duty to elicit from him in the witness box, evidence of the basis of his claim as an expert e.g. Professional training academic background and experience. And it is the duty of the opposing Counsel where appropriate, to cross-examine the said expert effectively in order to raise doubt as to the witness expertise. The evidence of an expert will amount to hearsay and therefore inadmissible where such expert gives his opinion on a report and is not called as a witness and cross-examined. See Shell Petroleum Development Co. v. Isaiah (1997) 6 NWLR Pt. 508 page 236.” Per ABOKI, J.C.A.( P. 71, Paras. D-G)
HOW TO EFFECTIVELY DISCREDIT THE EVIDENCE OF AN EXPERT.
The good news is that experts are not invisible. They are humans and also fallible. Notwithstanding the experience, skills or knowledge they may posses, the witness box has a way of revealing their weakness and the most intelligent man can be made to seem unintelligent when cross examined by a skillful lawyer. There are certain ways to discredit the evidence of an expert. I shall explain them hereunder.
1. RESEARCH.
Read the area or field which you will be cross-examinig the expert.One of the cardinal rules of cross examination is never to ask any questions which you do not know the answer. Do your research and find out things relating to that particular field.
Lawyers are often said to be learned because they know a little bit of everything. the lawyer has the ability to read up medical books and speak like a medical doctor. Reading up the topic and making further researches enables to lawyer to have a full grasp of the topic, this therefore makes it easier to ask questions that can discredit the evidence of an expert witness.
2. YOU CAN DISCREDIT AN EXPERT BY CALLING YOUR OWN EXPERT.
Where an expert gives an opinion on a particular field, you can discredit such an expert by calling another expert. Where there are conflicting views between two experts, the court is not bound by accepting either of the views. The court can suo motu reject same where it is not convincing. If the court is also faced with an evidence of two experts which are conflicting, the court will choose the most probable I.e the one it is likely to believe.
Wellman stated in his book “The Art of cross examination ” that it has become a matter of common observation that not only can the honest opinions of different experts be obtained upon opposite sides of the same question, but also that dishonest opinions may be obtained upon different sides of the same question. Attention is also called to the distinction between mere matters of scientific fact and mere matters of opinion. For example: certain medical experts may be called to establish certain medical facts which are not mere matters of opinion. On such facts the experts could not disagree; but in the province of mere opinion it is well known that the experts differ so much among themselves that but little credit is given to mere expert opinion as such”.
Even in academic world, we have different authors who have different views on the same issue, so this is also true in other fields, even in science where different experts have different opinions on the same subject matter.
3. RAISING DOUBT AS TO THE EXPERT’S EXPERTISE/SKILL
This can be done by checking the background and previews reports of the expert to find some loopholes. Also digging out reports of where the expert had claimed a contrary view of what is being stated. You can also raise questions that tend to prove the witness has no expertise or not active in the field which he profeses to be knowledgeable. For instance a medical doctor who does not practice claiming to know surgical procedures of which a doctor in active practice would be more familiar with.
in the case of AMOSUN v. INDEPENDENT NATIONAL ELECTORAL COMMISSION & ORS. [2010 – LPELR-CA/I/EPT/GOV/01/2009 it was established that where the court or tribunal is not satisfied that a witness is possessed of sufficient knowledge, training, experience and expertise on the subject of his evidence to qualify as a person specially skilled therein, then such witness cannot in law be regarded as an expert for the purpose of the subject, issue or point on which the court or tribunal has to form an opinion as contemplated by the provisions of Section 57(1).
According to Wellman in his book “The Art of cross examination” the whole effect of the testimony of an expert witness may sometimes effectually be destroyed by putting the witness to some unexpected and offhand test at the trial, as to his experience, his ability and discrimination as an expert, so that in case of his failure to meet the test he can be held up to ridicule before the jury, and thus the laughter at his expense will cause the jury to forget anything of weight that he has said against you”.
4. RAISING DOUBT AS TO THE WITNESS QUALIFICATIONS AND QUESTIONING THE AUTHENTICITY OF HIS DEGREE.
Generally an “expert” needs not have a degree before he can render an opinion’ The Evidence Act talks about qualification. The qualification envisaged depends on the circumstances of each case. A medical doctor surely needs to give evidence of the academic qualifications. A person learned in Yoruba customary law or Islamic law may not have a western education but may be accepted as qualified to give evidence. In an election petition if the expert opinion is limited to the addition and subtraction of votes already declared by the courts to be valid or invalid, then it will be acceptable.”Per OGUNWUMIJU, J.C.A.(P. 165, paras. C-F) AMOSUN v. INDEPENDENT NATIONAL ELECTORAL COMMISSION & ORS. Supra.
If the expert witness is unable to qualify due to his or her credentials in cases where it matters, it is easy to disqualify him or her. An application should be made to the court to disqualify the expert or that the testimony of the expert be rejected.
5. ASKING THE EXPERT QUESTIONS THAT ESTABLISHES HIS OPINION IS NOT IN ACCORD WITH COMMON SENSE.
In addition even where a person was determined to be an expert witness if his evidence is not in accord with common Sense or inconsistent with normal happenings, the court or tribunal is not bound to accept it but has a duty to reject it. AMU V. AMU (2000) 7 NWLR (PT.663)164, 174
ADELAKUN V. ORUKU (supra), CHUKWU CONSTRUCTION CO. LTD. V. UWECHIA (2000) 2 NWLR (PT.643) 92 AT 98.”Per GARBA, J.C.A.(P. 115, paras. C-G)
In Conclusion, expert witnesses can be discredited by a cross examiner if done skillfully. It would not be advisable for a cross examiner to try and outshine the the expert in his own field by engaging In long lengthy conversation with the expert or giving the expert opportunities to explain a particular Opinon or theories. This will be disastrous to the case of the cross examiner. Always endeavour to keep it short and precise.
Written by Mpi Elton Chizindu Esq.
Reference.
Wikipedia on definition of expert.
Black’s Law dictionary 8th edition on definition of expert.
Evidence Act.
Wellman’s View on the Art of Cross examination.
Ace Juris 