Who is an expert? When is the opinion of an expert relevant? What is the value of such an opinion in evidence?

Question: Who is an expert? When is the opinion of an expert relevant? What is the value of such an opinion in evidence? [U.P.C.J. 2018, UPHJS 2001]

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Answer

Section 45 of the Indian Evidence Act makes the opinion of persons specially skilled in some science, art, foreign law, the identity of handwriting and finger-impressions relevant.

The section also gives a definition of an expert witness. An expert is one who has acquired special knowledge, skill or experience in any science, art, trade or profession: such knowledge, may have been acquired by practice, observation or careful studies as held in Mahmood v. State of U.P., AIR 1976 SC 69.

In Bal Krishna Das Agrawal v. Radha Devi and others, [AIR 1989 All. 133] an expert was defined as a person who by his training and experience has acquired the ability to express an opinion but an ordinary witness does not possess this quality. The evidence of an expert is such evidence that is based on expertise and experience.

In view of the language of Section 45 of the Evidence Act, it is necessary that before a person can be characterized as an expert there must be some material on record to show that he is one who is skilled in that particular science and is possessed of particular knowledge concerning the same. He must have a special study of the subject or acquired special experience therein. Thus before the testimony of the witness became admissible his competency as an expert must be shown, may be by showing that he was possessed of necessary qualification or that he has acquired special skill therein by experience.

1. Prerequisites of expert evidence

Before expert testimony can be admitted two things must be proved, namely,

1. the subject is such that expert testimony is necessary; and
2. that the witness in question is really an expert, and that he is a truthful witness.

Expert (Testimony) Opinion was necessary.—Where the court was able to form its own opinion from facts and circumstances of the case it can be said that expert opinion was not necessary. But wherein some technical question is involved which can be answered by a person especially skilled it can be said that expert opinion was necessary.

The Witness in question is really an expert.—In order to bring the evidence of a witness as that of an expert it has to be shown that he made a special study of the subject or acquired a special experience therein or in other words that he is skilled and has adequate knowledge of the subject.

2. On what matters expert opinion can be given

The subjects on which an expert is competent to testify are: foreign law, matters of science, questions of art, identity of handwriting, or of finger impressions. The words ‘science’ or ‘art’ include all subjects on which the course of special study or experience is necessary to the formation of opinion. The matter in question must be of technical nature, or no expert can be permitted to speak on a matter with which the judge may be supposed to be equally well acquainted.

3. Value of expert opinion

The Evidence Act only provides about the relevancy of expert opinion but gives no guidance as to its value. It is often said that there cannot be any more unsatisfactory evidence than that of an expert. The value of expert opinion suffers from various drawbacks:

(i) There is the danger of error or deliberate falsehood. “These privileged persons might be half-blind, incompetent or even corrupt.”

(n) His evidence is after all opinion and “human judgment is fallible. Human knowledge is limited and imperfect”.

(iii) An expert witness, howsoever impartial he may be, is likely to be unconsciously prejudiced in favour of the side which calls him. Thus, expert witnesses are called witnesses “retained and paid” to support by their evidence a certain view on a scientific or technical question.

These factors seriously reduce the probative value of expert evidence. It would be highly unsafe to convict a person on the sole testimony of an expert.

The reliability of such evidence has, therefore, to be tested the same way in which any other piece of evidence is tested. The Supreme Court has laid down the following principles in this regard (Murari Lai v. State of M.P. AIR 1980 SC 531):

(i) There is no rule of law, nor any rule of prudence which has crystallised into a rule of law, that the opinion evidence of an expert must never be acted upon unless substantially corroborated.

(ii) But, having due regard to the various adverse factors operating in case of expert opinion, the approach should be one of caution. Reasons for the opinion must be carefully probed and examined. All other relevant evidence must be considered.

(iii) In appropriate cases, corroboration must be sought. In cases where the reasons for the opinion are convincing and there is no reliable evidence throwing a doubt, the uncorroborated testimony of an expert may be accepted.

(iv) The hazard in accepting the expert opinion, is not because experts, in general, are unreliable witnesses – the equality of credibility or incredibility being one which an expert shares with all other witnesses – but because all human judgment is fallible and an expert may go wrong because of some defect of observation, or honest mistake of conclusion. The more developed and more perfect a science, the less is the chance of an incorrect opinion.

The science of identification of fingerprints has attained near perfection and the risk of incorrect opinion is practically non-existent. On the other hand, the science of identification of handwriting is not so perfect and the risk is, therefore, higher. But that is far from doubting the opinion of a handwriting expert as an invariable rule and insisting upon substantial corroboration in every case, however, the opinion may be backed by the soundest of reasons.

(v) The opinion of an expert is not decisive or conclusive of the matter. The court should not surrender its opinion to that of the expert. An expert deposes and not decides. His duty is to furnish the judge with the necessary scientific criteria for testing the accuracy of his conclusion, so as to enable the judge to form his own independent judgment by the application of those criteria to the facts proved in evidence.

Hence, it is the duty of the court to remove the chaff from the grain and base its decision on the credible and reliable evidence of expert which doesn’t clinch with the case in hand. In Wilayat Khan v. State (AIR 1962 SC 122), it was held that expert opinion is not to be believed when it is in conflict with direct evidence. It has been held that medical evidence cannot be decisive of the matter. In case of any conflict between eye evidence and medical evidence, the court will have to go by the evidence which inspires more confidence.

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Important Mains Questions Series for Judiciary, APO & University Exams

1. Law of Evidence Mains Questions Series Part-I
2. Law of Evidence Mains Questions Series Part-II
3. Law of Evidence Mains Questions Series Part-III
4. Law of Evidence Mains Questions Series Part-IV
5. Law of Evidence Mains Questions Series Part-V
6. Law of Evidence Mains Questions Series Part-VI
7. Law of Evidence Mains Questions Series Part-VII
8. Law of Evidence Mains Questions Series Part-VIII
9. Law of Evidence Mains Questions Series Part-IX
10. Law of Evidence Mains Questions Series Part-X