Report No. 69

VIII. Questions to be Put to Experts

17.43. Hypothetical question-Introduction.-

As a general rule, the opinions of experts are admissible not only where they rest on the personal observations of the witness himself, and on facts within his knowledge, but also where they are merely founded on the facts as proved by other witnesses at the trial. The question whether the ex-pert ought to be asked to give his opinion on hypothetical questions, has been frequently discussed in academic literature. The present position on this point seems to be this. An expert may give his opinion upon-.

(a) facts proved by himself;

(b) facts proved by other witnesses;

(c) hypotheses based upon the evidence.

But his opinion is not admissible as to-

(i) facts stated out of court which are not before the court; or

(ii) facts which have merely been reported to him by hearsay; or

(iii) purely speculative hypothetical questions having no foundation in the evidence adduced.1

1. Woodroffe Law of Evidence, (1941), p. 453.

17.44. Rule explained.-

The meaning of the last mentioned rule has been thus explained1-

"In examination-in-chief it would tend to confusion if facts were assumed in hypothetical questions which did not bear upon the matters under inquiry or which were not fairly within the scope of any of the evidence. The testimony must tend to establish the facts embraced in the question. The Court should not, however, reject a question which, Counsel claims, embraces facts which the evidence tends to prove, simply because in its opinion the facts assumed are not established by a preponderance of the evidence. The question is properly allowable if there is any evidence tending to prove the facts assumed; it will not be allowed if the evidence does not prove or tend to prove the fact assumed. So, in a case involving the value to the plaintiff of a contract which the defendant had broken, a question which did not accurately state the terms of the contract was held inadmissible2".

Position in India as to hypothetical questions.-Hypothetical questions have been followed in India, in several cases3.

The facts of a Calcutta case Roghuni v. Q.E, 1882 ILR 9 Cal 455 (463), illustrate the necessity of questions, putting hypothetical questions. In that case, the Assistant Surgeon had actually seen the dead body, and had performed the post-mortem examination. The Court observed that his evidence, as that of a medical expert, was, therefore, admissible, "first, to prove the nature of the injuries which he observed on the dead body; and, secondly, as opinion-evidence with respect to the manner in which those injuries were inflicted, and the cause of death."

Dr. Shaw, another medical expert, who was called to give his opinion, had not seen the dead body, and had not made the post-mortem examination. The Court held, that Dr. Shaw was in the position of an "expert witness who could give nothing but opinion-evidence." The Court observed, that the general rule as to evidence of this kind is that the questions must be put to the witness hypothetically, put in this way:

"Assuming such and such facts to be true, what is your opinion on the matter?" "Assuming such and such an injury, an injury of such and such a kind to have been inflicted, what is your opinion as to the nature of the weapon by which it was possibly or probably inflicted?"

1. Woodroffe Law of Evidence, (1941), p. 453.

2. Lawson's Expert Evidence, 222 and Rogers Expert Testimony, 64, 68, cited.

3. (a) Drachenfels, 1900 ILR 27 Cal 860.

(b) Roghuni Singh v. Emperor, 1882 ILR 9 Cal 455 (461) (Mitter and Field, B.).

(c) R. v. Meher, 1888 ILR 15 Cal 589.

(d) Deorao v. Emp., AIR 1946 Nag 320 (335), para. 62.

The High Court added-

"The facts thus hypothetically stated to the witness would, of course, be the facts which the evidence of the other witnesses in the case attempted to prove, and as to which it was for the jury to find whether they had been proved or not."

In another Calcutta case1, the facts were as follows:

During the trial, Dr. Mackenzie, the Police Surgeon, was called to give evidence as to the cause of death, and in the course of his evidence he stated the various marks and indications he found when making the post-mortem examination, and gave it as his opinion that death was due to asphyxia caused by strangulation. This opinion was challenged by counsel for the defence. and Dr. Mackenzie was cross-examined to show that death had not been caused as alleged. Subsequently, the prosecution called another witness, Dr. Macleod, who had not been present at the post mortem and had not been called before the Magistrate, nor had he had anything to do with the case, the defence having been previously furnished with a statement of what Dr. Macleod was called to prove.

Dr. Macleod was put in the box. The appearance of the body as spoken t by Dr. Mackenzie, together with the signs spoken to by him as having bee noticed by him when making the post mortem examination, were put to hin and he was asked this question-"upon these facts what in your opinio would be the cause of death."

Dr. Macleod was put in the box. The appearance of the body as spoken to by Dr. Mackenzie, together with the signs spoken to by him as having been noticed by him when making the post mortem examination, were put to him, and he was asked this question- "upon these facts what in your opinion would be the cause of death."

Counsel for the accused objected to the question. The objection was to the effect, that such a question was admissible only when the facts were admitted and the question was purely relating to medical science. Here the facts were not admitted, and the only question that could be put was, what are the usual indications of death by strangulation.

The court rejected the objection, relying upon Roghuni's case2, because the question did not involve the truth of the evidence. In a case before the Bombay High Court3 (arising out of an appeal against the decision of the Commissioner for Worker's Compensation), it was argued that the Commissioner should not have accepted the evidence of a doctor who had not examined the patient and whose evidence was based on probabilities. The High Court rejected this objection, and observed,-

"But an expert is entitle to answer all hypothetical questions put to him. The only safeguard which we must apply is that the hypotheses are correctly put to the expert."

Hypothetical questions in England.- Hypothetical questions are allowed in England.-5 also.

1. Q.E. v. Meher Ali Mullick, 1888 ILR 15 Cal 589 (594) (Wilson, J.).

2. Roghuni v. Q.E., 1882 ILR 9 Cal 455.

3. Bai Diya v. Silver Cotton Mills, AIR 1956 Born 424 (425) (Chagla, C.J. and Dtxit, J.).

4. Phipson Evidence, (1967), para. 1298.

5. See "English cases", infra.

Hypothetical questions in U.S.A.- It appears that hypothetical questions have been the subject matter of some criticism in the U.S.A. The view of Wigmore may be referred to on this point1.

"The hypothetical question must go. The hypothetical question, misused by the clumsy and abused by the clever, has in practice led to intolerable obstruction of truth. In the first place, it has artificially clamped the mouth of the expert witness, so that his answer to a complex question may not express his actual opinion on the actual case. This is because the question may be so built up and contrived by counsel as to represent only a partisan conclusion. In the second place, it has tended to mislead the jury as to the purport of actual expert opinion. This is due to the same reason. In the third place, it has tended to confuse the jury, so that its employment becomes a mere waste of time and a futile obstruction.

No partial limitation of its use seems feasible, by specific rules. Logically, there is no place to stop short; practically, any specific limitations would be more or less arbitrary, and would thus tend to become mere quibbles. How can the extirpating operation be performed? By exempting the offering party from the requirement of using the hypothetical form; by according him the opinion of using it-both of these to be left to the trial Court's discretion; and by permitting the opposing party, on cross-examination, to call for a hypothetical specification of the data which the wit-ness has used as the basis of opinion. The last rule will give sufficient protection against a misunderstanding of the opinion, when any actual doubt exists."

Provision as to hypothetical questions in Model Expert Testimony Act, U.S.A.-In the Model Act on Expert Testimony framed in the U.S.A., the provision as to the questions to be put to an expert witness is as follows2:-

1. Wigmore Evidence, (1923), section 686, cited in the Commissioner's Note to the Model Expert Testimony Act, section 9.

2. Model Expert Testimony Act, section 9.

"9. Examination of Experts

(1) An expert witness may be asked to state his inferences, whether these inferences are based on the witness' personal observation, or on evidence introduced at the trial and seen or heard by the witness, or on his technical knowledge of the subject, without first specifying hypothetically, in the question, the data on which these inferences are based.

(2) An expert witness may be required, on direct or cross-examination, to specify the data on which his inferences are based.

The object of the section in the Model Act has been thus explained1:

The aim of this section is to remedy a major evil. The courts have supported the proposition, when an expert has testified to the facts, that no hypothetical question is necessary. The courts also generally tend to permit an opinion based upon the truth of a particular witness' testimony, and some have even gone to the length of permitting an opinion to be based upon all the facts given in evidence where they are not in conflict. The statute proposed goes one step further and would permit an opinion in all cases irrespective of conflict, insuring, however, a full and complete elucidation of the underlying premises through cross-examination for the benefit of the jury. The expert states his opinion as formulated from his attendance upon the testimony given or from a draft of the testimony which he has read.

Upon cross-examination the particular facts which he has considered, together with the weight and construction he has put upon them, can be dissected and examined. Although this has not been the regular practice, it is not without the confirmation of the courts. See Beckwith v. Sydebothatn, 1 camp. 116, 117, 170 Eng. Re. 897 (1807): Commonwealth v. Johnson, 188 Mass. 382 (1905). There is here no attempt to obstruct or limit the jury in its determination of the ultimate fact. It may be urged that the opinion admitted cannot be completely destroyed, regard-less of the result of the subsequent cross-examination.

This contention has little weight, for surely counsel can be relied upon to inform the jury the extent to which the expert's view is supported by the facts. It should be observed, also, that under the system of hypothetical examination it is common to cut out, as far as possible, all facts which might lead to an adverse response and so frame the question that the resulting answer sup-ports counsel's view. How can it be said that an opinion based upon all the facts compares unfavourably in effect with a palpably erroneous one forced from the premise of distorted facts.

The principal objection to the hypothetical question, aside from the fact that it is expensive and tedious, is that in practical effect it achieves just what it was designed to remedy. It has been termed by Justice Hodmes "a logical necessity but a practical incubus". The longdrawn-out hypothetical question, instead of assisting the jurors, confuses and misleads them until they are forced to abandon expert opinion entirely and decide the issue upon other grounds.

1. Model Expert Testimony Act, Commissioners' Note.

(The Note then quotes the suggestion made by Wigmore].

English Case-In the English case of Beckwith v. Sydebotham, (1807) 1 Camp 116, Lord Ellerborough allowed shipwrights to testify concerning the seaworthiness of a ship. He said that where there was a matter of skill or science to be decided, the jury might he assisted by the opinion of those peculiarly acquainted with it in their professions or pursuits; as the truth of the facts stated in them was not certainly known, their opinion might not go for much; but still it was admissible evidence. In cross-examination, they might be asked what they would think on the state of facts contended for by the other side.

View of Cross.- Lord Ellenborough was, in Beckwith v. Sydeborharn, (1807) 1 116 camp 116, supra., referring to a difficulty that is encountered in the reception of all kinds of expert evi-dence. "In the vast majority of cases, the witnesses will not have perceived the occurrences with which the case is concerned. In Beckwith v. Sydebotham, for instance, the shipwrights had not examined the ship whose sea-worthiness was in issue, therefore their opinion had to be based on assumed facts. It is for the court to determine which party's version of the occurrences in issue is to be accepted. Accordingly, every effort must be made not to call upon the expert to give an opinion on the veracity of the ordinary witnesses in the case, or the validity of any inference concerning the existence of a disputed fact. This can only be done by forming a series of hypothetical questions--a procedure which, however necessary it may he, certainly complicates the issues in a particular case."

Conclusion regarding hypothetical questions.- We have taken note of this criticism, and also of the provision suggested in the U.S.A. on the subject. It appears to us, however, that in the cases are conflicting as to how an expert may be asked the very question which the jury have to decide; but the weight of authority appears to be as follows: (a) Where the issue involves other elements besides the purely scientific, the expert must confine himself to the latter, and must not give his opinion on the legal or general merits of the case; (b) Where the issue is substantially one of science or skill merely, the expert may, if he has himself observed the facts, be asked the very question which the jury have to decide.

If, however, his opinion is based merely upon facts proved by others, such a question is improper, for it practically asks him to deter-mine the truth of their testimony, as well as to give an opinion upon it; the correct course is to put such facts to him hypothetically, but not en bloc, asking him to assume one or more of them to be true, and to state his opinion thereon; where, however, the facts are not in dispute, it has been said that the former question may be put as a matter of convenience, though not as of right."

Position in India.- So far as the position in India is concerned, the language of section 45 is wide enough to cover opinion as to facts in issue. In India, the objections to a hypothetical question would not be so strong as elsewhere, as the trial in India is by the Judge and not by jury. A Judge is not likely to be mislead or confused by hypothetical questions. Moreover, there, are occasions when a hypothetical question is useful and may even be a necessity, as in the case of conflicting evidence when it is not possible to say what version will or will not ultimately be accepted by the Court as true. Further, a hypothetical question need not always be complex; it can be a simple one, requiring only a small number of assumed facts. Although we are not recommending any new provision on the subject, the above is the correct position in our view.

Ultimate issues and expert evidence.- Another interesting matter concerning the questions that can be put to an expert witness is this-can the expert be asked to have an opinion on the very matter which is to be decided by the Court (i.e. the Act in issue)?

English law.-In Errgland, the law on the subject has been thus stated1-

1. Phipson Evidence, (1967) 1 Compt 116, supra.

a. The paras. have not been numbered hereinafter, in the Report, as published by the Law Commission.

(See Phipson Evidence (1967) 1 Compt 116)

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