Law relating to Expert Opinion under the Indian Evidence Act


February 16, 2018

The Indian Evidence Act under Section 45 enumerates the law relating to Opinion of Experts or commonly known as Expert Opinion/Expert evidence. This statutory provision is adhered to when the Court has to form opinion pertaining to:

  • -foreign law
  • -science
  • -identity of handwriting
  • -finger impressions

In such cases, the Court seeks opinion of skilled persons i.e. experts in the aforementioned fields. Matters commonly made the subject of such evidence include causes of death, insanity, effects of poison, genuineness of works of art, value of articles, genuineness of handwriting, proper navigation of vessels, meaning of trade terms and foreign law[1]. A witness who is qualified to speak on these matters is called an expert.

Importance of Expert Opinion

The Supreme Court in the case of State of H.P. v. Jai Lal and Ors.[2] explained the substance of expert opinion by stating that Section 45 of the Evidence Act which makes opinion of experts admissible lays down, that, when the court has to form an opinion upon a point of foreign law, 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, science or art, or in questions as to identity of handwriting, or finger impressions are relevant facts. Therefore, in order to bring the evidence of a witness as that of an expert it has to be shown that he has 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.

Requirements of Expert evidence

The Supreme Court in the case of Ramesh Chandra Agrawal vs Regency Hospital Ltd. & Ors.[3] delineated the requirements of an expert evidence under Section 45 of the Evidence Act. The Court stated that the first and foremost requirement for an expert evidence to be admissible is that it is necessary to hear the expert evidence. The test is that the matter is outside the knowledge and experience of the lay person. Thus, there is a need to hear an expert opinion where there is a medical issue to be settled.

The scientific question involved is assumed to be not within the court’s knowledge. Thus cases where the science involved, is highly specialized and perhaps even esoteric, the central role of expert cannot be disputed. The other requirements for the admissibility of expert evidence are:

  • that the expert must be within a recognized field of expertise
  • that the evidence must be based on reliable principles, and
  • that the expert must be qualified in that discipline.

 Who is an “expert”?

The Act does not enumerate any qualification or standard for being categorized as an expert under Section 45 of the Evidence Act. The term used by the provision is “persons specially skilled”. In order to have a broader understanding of the term it would be preferable to illustrate the same through precedents.

The Supreme Court in the case of State of Himachal Pradesh Vs. Jai Lal and others[4] in the following words explained who an expert is and what his functions are.

  • An expert witness, is one who has made the subject upon which he speaks a matter of particular study, practice; or observations; and the must have a special knowledge of the subject.
  • In order to bring the evidence of a witness as that of an expert it has to be shown that he has 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.
  • An expert is not a witness of fact. His evidence is really of an advisory character. The duty of an expert witness is to furnish the Judge with the necessary scientific criteria for testing the accuracy of the conclusions so as to enable the judge to form his independent judgment by the application of this criteria to the facts proved by the evidence of the case.
  • The scientific opinion evidence, if intelligible, convincing and tested becomes a factor and often an important factor for consideration along with the other evidence of the case. The credibility of such a witness depends on the reasons stated in support of his conclusions and the data and materials furnished which form the basis of his conclusions.

One of the earliest cases which enumerated on the function of expert was Titli v. Jones[5], wherein it was stated that the real function of the expert is to put before the court all the materials, together with reasons which induce him to come to the conclusion, so that the court, although not an expert, may form its own judgment by its own observation of those materials.’

What is the Evidentiary value of Expert Opinion?

A Court is not bound by the evidence of the experts which is to a large extent advisory in nature. The Court must derive its own conclusion upon considering the opinion of the experts which may be adduced by both sides, cautiously, and upon taking into consideration the authorities on the point on which he deposes[6].

The value of expert opinion rest on the facts on which it is based and his competency for forming a reliable opinion. The evidentiary value of the opinion of expert depends on the facts upon which it is based and also the validity of the process by which the conclusion is reached. Where the experts give no real data in support of their opinion, the evidence even though admissible, may be excluded from consideration as affording no assistance in arriving at the correct value[7].

The Allahabad Court in one of the earliest cases pertaining to the issue in question stated that the value of expert evidence depends largely on the congency of the reasons on which it is based. In general it cannot be the base of conviction unless it is corroborated by other evidence[8].

Evidence of experts after all is opinion evidence. The opinion is to be supported by reasons. The Court has to evaluate the same like any other evidence. The reasons in support of the opinion, if convincing, make the opinion acceptable. There is no place for ipse dixit of the expert. It is for the court to judge whether the opinion has been correctly reached on the data available and for the reasons stated[9]. Hence, from the judicial pronouncements it can be inferred that expert evidence or opinion is not a cogent or conclusive evidence and to make it a stronger evidence in a case it has to be supported by reasons and relevant data.

Thus, no expert can claim that he could be absolutely sure that his opinion was correct, expert depends to a great extent upon the materials put before him and the nature of question put to him[10].

Is it necessary to corroborate Expert Evidence?

This legal aspect has been considered by the Judiciary in several cases and there has been a dichotomy of opinion. However, the Supreme Court in the case of Murari Lal v. State of M.P.[11] appears to have settled the issue by stating that on the facts of a particular case, a court may require corroboration of a varying degree. There can be no hard and fast rule, but nothing will justify the rejection of the opinion of an expert supported by unchallenged reasons on the sole ground that it is not corroborated. The approach of a court while dealing with the opinion of a handwriting expert should be to proceed cautiously, probe the reasons for the opinion, consider all other relevant evidence and decide finally to accept or reject it.

Evidence of handwriting expert

The issue relating to evidence of a handwriting expert has been expounded by the Courts in plethora of judgments. In the case of State of Maharashtra v. Sukhdeo Singh[12], the Apex Court opined that before a Court can act on the opinion evidence of a handwriting expert two things must be proved beyond any manner of doubt, namely, (i) the genuineness of the specimen/admitted handwriting of the concerned accused and (ii) the handwriting expert is a competent, reliable and dependable witness whose evidence inspires confidence.




[1] Cokel’s Cases and Statutes on Evidence (6th Edn. 1970)

[2] [(1999) 7 SCC 280]

[3] [2009] INSC 1569

[4] AIR 1999 SC 3318

[5] AIR 1934 All 237

[6] Malay Kumar Ganguly v. Sukumar Mukherjee

[7] Extract from the Article “Relevancy of Expert’s Opinion”

[8] Saqlain Ahmad v. Emperor AIR 1936 Alld. 165

[9] State Vs. Kanhu Charan Barik 1983 Cr.L.J. 133

[10] The State (Delhi Administration) v. Pali Ram, AIR 1979 SC 14

[11] [1980] 1 SCC 704

[12] 1992 AIR 2100