Evidentiary value of Expert opinion.

 

It is a general rule that a witness must confine himself to the facts and not to state his opinion. Forming of opinions on basis of the evidence adduced before the Court is a judicial function of the Court and it cannot delegate this function to the witnesses in regard to the matters which are under enquiry. But sometime, when a subject matter before the Court partakes of the character of science or art where special skill, special training or special study is required for the formation of an opinion, then the Court may seek the assistance of the persons who are specially skilled or specially trained in that subject-matter. Such person who is specially skilled or trained is called an expert.

Section 45 of the Indian Evidence Act, 1872 postulates the relevancy of opinion of third person i.e. expert. The section also gives a definition of an expert witness.

According to the Section “ 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 finder 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 finder impressions are facts and such persons are called expert.

There are two prerequisite, before the expert testimony is admitted by the court. They are –

1. the subject matter 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.

It is necessary that the competency of the expert witness whose testimony is to be admitted must be satisfactorily established. It is for the Court to determine the competency of an expert witness. in determining the competency of the expert, the Court may have to take the qualifications, experience, training and study, possessed by the expert in the particular filed to which the courts enquiry pertains.

            The opinion of expert can also be contradicted and rebutted by showing that he gave a different opinion on other occasion in a similar matter or by producing a standard treatise relevant to the subject matter of enquiry. The opinion of an expert witness can also be contradicted by engaging another expert witness.

 

            EVIDENTIARY VALUE OF EXPERT OPINION

        Expert evidence is advisory in nature. It is not conclusive. The weight of the evidence depends on the correctness of the report, the reasons given and the expertise of the expert in the field. Court is not bound to accept the opinion of the expert. It is not a substantive piece of evidence rather only corroborative in nature.

The Apex Court of India in Krishnan And Anr vs. State Represented by Inspector of Police reported in AIR 2003 SC 2978 categorically held that it would be erroneous  to accord undue primacy to the hypothetical answer of medical witnesses to exclude the eye witnesses account which had to be tested independently and not treated as variable keeping the medical evidence as constant. It is trite that where the eye witnesses’ account is found credible and trustworthy, medical opinion pointing to alternative possibilities is not accepted as conclusive.

In Dayal Singh & Ors vs. State of Uttranchal (2012) the Supreme Court viewed,  “the Court normally, look at expert evidence with a greater sense of acceptability, but is equally true that the courts are not absolutely guided by the report of the experts, especially if such reports are per functionary, unsustainable and are the result of a deliberate attempt to misdirect the prosecution”.

            Thus, expert evidence is only a piece of evidence and weight to be given to it has to be judged along with other evidences of this nature is ordinarily not conclusive. Such evidence therefore cannot be taken as substantial piece of evidence unless corroborated by other evidence. The evidence of experts are not binding upon the judge.