Judiciary aspires to reach a comprehensive, unambiguous, just, and fair conclusion in a matter with the help of evidence before it.1 Sometime, courts/arbitral tribunals are unable to assess certain evidence due to its technicalities. Therefore, expert evidence comes for judicial assistance. Initially, the Courts restricted the assistance of experts in limited fields like medical doctors, engineers, stockbrokers etc. However, the need of expert opinion increased with the vast development in science and technology, and the role of experts has been widened. Whenever the Court/arbitral tribunal requires forming an opinion on technical issues related to foreign law/science/art, the Court can ask expert's unbiased and scientific opinion on technical issues related to foreign law/science/art, on which the court is unlikely to2 form correct opinion. No specific definition of Expert Evidence could be traced in Indian Evidence Act, 1872. Expert is understood as a person who devotes his time, study, observation and practice to a special experience and possesses high knowledge and skill in a3 particular field, whereas Evidence is understood as information that proves truthfulness of disputed fact. Therefore, Expert evidence is information/opinion/statement made on disputed fact by experts of a particular field.

Parties of suit can present expert evidence to strengthen their case, which allows opposite party to cross-examine the Expert by virtue of principle of equity and fair play. But, considering the technicalities involved, it becomes difficult for a lawyer to cross-examine the expert witness. Therefore, this Article attempts to provide a framework to conduct cross-examination of an expert witness. Prior to that, this Article also analyses the relevancy and admissibility of Expert Evidence to understand the value of expert evidence in adjudication.


The expert's opinion is merely advisory and not4 binding on the Court. The expert opinion cannot be used for conclusive proof but merely acts as corroborative evidence. However, any irrelevant fact may become relevant, if they are consistent5 with the expert's opinion or vice versa. Documentary opinion of expert along with the data in support of his opinion is not sufficient, he must be cross-examined in the court because an6 expert like any other witness is fallible . Without examination, expert evidence would be7 admissible, but no reliance can be placed on it. Further, the expert should confine himself to relevant facts.

Therefore, the opinion of an expert which was8 not sought for should be ignored. Expert Opinion is a data evidence and cannot get9 precedence over the oral evidence unless the inconsistency between the two is so great as to obviously falsify the oral evidence unless the expert opinion is corroborated with independent10 and reliable evidence. In case of conflict between opinions of two experts, the Court would accept the expert's opinion which is consistent with direct evidence.


In para 29 of Bal Krishna Das Agarwal vs.11 Radha Devi, the Hon'ble Court observed that, "the expert should be subjected to crossexamination because an expert like any other witness is fallible and the real value of his evidence consists in the rightful inferences which he draws from what he has himself observed and not from what he merely surmises". It could be deduced that cross-examination of an expert is crucial for trial and consideration of the corroborative value of the expert's opinion. Often, one's case depends primarily upon the expert's report and his testimony before the Court/Ld. Arbitral Tribunal. Therefore, prior to the cross-examination of any expert, an indepth analysis of the expert's evidence with the help of the clients and their expert witness who has command over the concerned subject matter is the sine qua non.

A lawyer should identify all such portions of the expert report wherein the adverse expert witness has supported their case and should have clarity about the grey areas in the expert report to target the expert witness. During the cross examination, apart from the fact in issue, the expert witness can be questioned and tested on the following key thresholds:

1.1 Independency and Impartiality of the Expert Witness

The role of appointed expert witness is not to support the case of the side who has appointed it but to aid/assist the Hon'ble Court/Arbitral Tribunal in analysing the fact in issue or the set of relevant facts which involves analysis of complex, technical and specialised areas. If it is demonstrated during the cross examination that the opinion of the expert is biased or based on information/facts favourable to only one side, the Court/Arbitral Tribunal can doubt the reliability of entire expert report. Enquiries can also be made about the past or present relationship of the witness with the party who has appointed him/her.

1.2 Qualification of the Expert Witness

The expert is supposed to have requisite professional qualification in form of knowledge and experience, to form an opinion pertaining to the subject matter involved. Such an opinion will be authoritative and reliable only if the expert is qualified enough to evaluate all the aspects related to the subject matter. Therefore, during the cross examination, it is very relevant to examine academic and professional experience in the concerned field.

Also, in the present times, the disputes involve complex matters wherein more than the academic qualification, the practical expertise of the expert witness becomes relevant. So, even if an expert professional has stellar academic record, it is advisable to target practical insights and experience in the specific field.

1.3 Consistency in Opinion expressed by the Expert Witness

It is very pertinent to study any past report or opinion of the expert related to the same or similar fact in issue. Many times, there is an express or implied contradiction between the opinions which has been expressed by the witness in the present dispute and the opinion that he/she has expressed in previous cases. If there is any such opinion available in the public forum which is contrary to the present stance taken by the expert, the same will be sucient to raise substantial doubts about the reliability and objectivity of the expert report. Also, if there are various proceedings pending with respect to the same dispute, it is relevant to point out the contradictions or favourable admissions in the past reports and testimony of the same expert witness. Many times, the party even shows that the particular expert professional has some preoccupied notions about the fact in issue, due to which he has reached to a particular conclusion in this report.

According to the provision provided under the Evidence Act of 1872, the creditability of any witness can be impeached if there are glaring inconsistencies/contradictions between his12 present and past statements.

Similarly, while dealing with the similar issue in the case of V. K. Mishra and another Vs. State of13 Uttarakhand and another, the Apex Court has observed that, "under Section 145 of the Evidence Act, when it is intended to contradict the witness by his previous statement reduced into writing, the attention of such witness must be called to those parts of it which are to be used for the purpose of contradicting him, before the writing can be used."

1.4 Scope of Instructions

Usually, the expert specifies the scope of all the instructions that they have received, series of facts on which they have relied and a list of all the documents as well as other evidence that they have considered. Therefore, during the course of questioning, the following aspects of the expert reports can be targeted:

  • Whether the expert has reached to a valid conclusion which is related to the initial instructions given to him by the parties?
  • Whether the result of such report is relevant for the concerned proceedings i.e., if it is related to the fact is an issue of the dispute or not?
  • Whether the expert has placed reliance on those facts only which are favouring the party who has appointed him?
  • Whether the expert has placed reliance on those evidence which have been brought on record by the party who has appointed him?

1.5 Methodology adopted by the Expert

Questions should not only target the outcome or result of the expert report, but it should also be directed toward the methodology or process which the expert has adopted for preparing the14 report. As per the Daubert Standard, following are the five major factors which can be examined, in order to ascertain the reliability of the methodology adopted by the scientific expert:

  • Whether it can be or has been tested or not?
  • Whether it has been subjected to peer review and publication?
  • Is there any know or potential rate of error in the methodology involved?
  • Is there any maintenance of standards governing the applicability and operations of the said methodology?
  • Whether the technique widely known and acceptable with the relevant scientific community?


The expert's opinion is merely advisory. Despite being corroborative evidence, it could influence the decision of the Court/Arbitral Tribunal. Therefore, the purpose of the expert evidence should never be to prove claims which have been advanced by one party. The main aim of the expert witness is to help the court in fact finding process by providing clarity over the complex issues involved.

It is very pertinent to have this idea in mind while examining the expert witness. Also, cross examination is not a complex art. Rather, it is a simple process of fact finding based on logical tact and a reliable background search by the lawyer. By following above mentioned provisions and procedures, any legal practitioner can deal effectively with the daunting task to examining the expert witness.


1. Section 26, The Arbitration and Conciliation Act, 1996, Act 26 of 1996.

2. Section 45, The Indian Evidence Act, 1872, Act 01 of 1872.

3. Ramesh Chandra Agarwal vs. Regency Hospital Ltd., Civil Appeal No. 5991 of 2002, The Supreme Court of India, September 11, 2009.

4. Malay Kumar Ganguly vs. Dr. Sukumar Mukherjee, CRIMINAL APPEAL NOS. 1191-1194 OF 2005, The Supreme Court of India, August 07, 2009.

5. Section 46, The Indian Evidence Act, 1872, Act 01 of 1872.

6. Bal Krishna Das Agarwal vs. Radha Devi, AIR 1989 All 133.

7. State of Maharashtra vs. Damu Gopinath Shinde, AIR 2000 SC 1691.

8. Kabul Singh Vs. Gurinder Singh, MANU/PH/0679/1999.

9. Arshad vs. State of A.P, 1996 CrLJ 2893 (AP).

10.S. Gopal Reddy vs. State of A.P, AIR 1996 SC 2184.

11. Bal Krishna Das Agarwal vs. Radha Devi, AIR 1989 All 133.

12.Section 155 (3), The Indian Evidence Act, 1872, Act 01 of 1872.

13. V. K. Mishra and another vs. State of Uttarakhand and another, (2015) 9 SCC 588.

14. Daubert Et Ux., Individually and As Guardians Ad Litem for Daubert, Et Al. Versus Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993).

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.