Rule 606. Juror’s Competency as a Witness

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(a) At the Trial. A juror may not testify as a witness before the other jurors at the trial. If a juror is called to testify, the court must give a party an opportunity to object outside the jury’s presence.

(b) During an Inquiry into the Validity of a Verdict or Indictment.

(1) Prohibited Testimony or Other Evidence. During an inquiry into the validity of a verdict or indictment, a juror may not testify about any statement made or incident that occurred during the jury’s deliberations; the effect of anything on that juror’s or another juror’s vote; or any juror’s mental processes concerning the verdict or indictment. The court may not receive a juror’s affidavit or evidence of a juror’s statement on these matters.

(2) Exceptions. A juror may testify about whether:

(A) extraneous prejudicial information was improperly brought to the jury’s attention;

(B) an outside influence was improperly brought to bear on any juror; or

(C) a mistake was made in entering the verdict on the verdict form.


(Pub. L. 93–595, §1, Jan. 2, 1975, 88 Stat. 1934; Pub. L. 94–149, §1(10), Dec. 12, 1975, 89 Stat. 805; Mar. 2, 1987, eff. Oct. 1, 1987; Apr. 12, 2006, eff. Dec. 1, 2006; Apr. 26, 2011, eff. Dec. 1, 2011.)

Notes of Advisory Committee on Proposed Rules

Subdivision (a). The considerations which bear upon the permissibility of testimony by a juror in the trial in which he is sitting as juror bear an obvious similarity to those evoked when the judge is called as a witness. See Advisory Committee's Note to Rule 605. The judge is not, however in this instance so involved as to call for departure from usual principles requiring objection to be made; hence the only provision on objection is that opportunity be afforded for its making out of the presence of the jury. Compare Rules 605.

Subdivision (b). Whether testimony, affidavits, or statements of jurors should be received for the purpose of invalidating or supporting a verdict or indictment, and if so, under what circumstances, has given rise to substantial differences of opinion. The familiar rubric that a juror may not impeach his own verdict, dating from Lord Mansfield's time, is a gross oversimplification. The values sought to be promoted by excluding the evidence include freedom of deliberation, stability and finality of verdicts, and protection of jurors against annoyance and embarrassment. McDonald v. Pless, 238 U.S. 264, 35 S.Ct. 785, 59 L.Ed. 1300 (1915). On the other hand, simply putting verdicts beyond effective reach can only promote irregularity and injustice. The rule offers an accommodation between these competing considerations.

The mental operations and emotional reactions of jurors in arriving at a given result would, if allowed as a subject of inquiry, place every verdict at the mercy of jurors and invite tampering and harassment. See Grenz v. Werre, 129 N.W.2d 681 (N.D. 1964). The authorities are in virtually complete accord in excluding the evidence. Fryer, Note on Disqualification of Witnesses, Selected Writings on Evidence and Trial 345, 347 (Fryer ed. 1957); Maguire, Weinstein, et al., Cases on Evidence 887 (5th ed. 1965); 8 Wigmore §2340 (McNaughton Rev. 1961). As to matters other than mental operations and emotional reactions of jurors, substantial authority refuses to allow a juror to disclose irregularities which occur in the jury room, but allows his testimony as to irregularities occurring outside and allows outsiders to testify as to occurrences both inside and out. 8 Wigmore §2354 (McNaughton Rev. 1961). However, the door of the jury room is not necessarily a satisfactory dividing point, and the Supreme Court has refused to accept it for every situation. Mattox v. United States, 146 U.S. 140, 13 S.Ct. 50, 36 L.Ed. 917 (1892).

Under the federal decisions the central focus has been upon insulation of the manner in which the jury reached its verdict, and this protection extends to each of the components of deliberation, including arguments, statements, discussions, mental and emotional reactions, votes, and any other feature of the process. Thus testimony or affidavits of jurors have been held incompetent to show a compromise verdict, Hyde v. United States, 225 U.S. 347, 382 (1912); a quotient verdict, McDonald v. Pless, 238 U.S. 264 (1915); speculation as to insurance coverage, Holden v. Porter, 495 F.2d 878 (10th Cir.1969), Farmers Coop. Elev. Ass'n v. Strand, 382 F.2d 224, 230 (8th Cir. 1967), cert. denied 389 U.S. 1014; misinterpretations of instructions, Farmers Coop. Elev. Ass'n v. Strand, supra; mistake in returning verdict, United States v. Chereton, 309 F.2d 197 (6th Cir. 1962); interpretation of guilty plea by one defendant as implicating others, United States v. Crosby, 294 F.2d 928, 949 (2d Cir. 1961). The policy does not, however, foreclose testimony by jurors as to prejudicial extraneous information or influences injected into or brought to bear upon the deliberative process. Thus a juror is recognized as competent to testify to statements by the bailiff or the introduction of a prejudicial newspaper account into the jury room, Mattox v. United States, 146 U.S. 140 (1892). See also Parker v. Gladden, 385 U.S. 363 (1966).

This rule does not purport to specify the substantive grounds for setting aside verdicts for irregularity; it deals only with the competency of jurors to testify concerning those grounds. Allowing them to testify as to matters other than their own inner reactions involves no particular hazard to the values sought to be protected. The rules is based upon this conclusion. It makes no attempt to specify the substantive grounds for setting aside verdicts for irregularity.

See also Rule 6(e) of the Federal Rules of Criminal Procedure and 18 U.S.C. §3500, governing the secrecy of grand jury proceedings. The present rules does not relate to secrecy and disclosure but to the competency of certain witnesses and evidence.

Notes of Committee on the Judiciary, House Report No. 93–650

As proposed by the Court, Rule 606(b) limited testimony by a juror in the course of an inquiry into the validity of a verdict or indictment. He could testify as to the influence of extraneous prejudicial information brought to the jury's attention (e.g. a radio newscast or a newspaper account) or an outside influence which improperly had been brought to bear upon a juror (e.g. a threat to the safety of a member of his family), but he could not testify as to other irregularities which occurred in the jury room. Under this formulation a quotient verdict could not be attacked through the testimony of a juror, nor could a juror testify to the drunken condition of a fellow juror which so disabled him that he could not participate in the jury's deliberations.

The 1969 and 1971 Advisory Committee drafts would have permitted a member of the jury to testify concerning these kinds of irregularities in the jury room. The Advisory Committee note in the 1971 draft stated that “* * * the door of the jury room is not a satisfactory dividing point, and the Supreme Court has refused to accept it.” The Advisory Committee further commented that—

The trend has been to draw the dividing line between testimony as to mental processes, on the one hand, and as to the existence of conditions or occurrences of events calculated improperly to influence the verdict, on the other hand, without regard to whether the happening is within or without the jury room. * * * The jurors are the persons who know what really happened. Allowing them to testify as to matters other than their own reactions involves no particular hazard to the values sought to be protected. The rule is based upon this conclusion. It makes no attempt to specify the substantive grounds for setting aside verdicts for irregularity.

Objective jury misconduct may be testified to in California, Florida, Iowa, Kansas, Nebraska, New Jersey, North Dakota, Ohio, Oregon, Tennessee, Texas, and Washington.

Persuaded that the better practice is that provided for in the earlier drafts, the Committee amended subdivision (b) to read in the text of those drafts.

Notes of Committee on the Judiciary, Senate Report No. 93–1277

As adopted by the House, this rule would permit the impeachment of verdicts by inquiry into, not the mental processes of the jurors, but what happened in terms of conduct in the jury room. This extension of the ability to impeach a verdict is felt to be unwarranted and ill-advised.

The rule passed by the House embodies a suggestion by the Advisory Committee of the Judicial Conference that is considerably broader than the final version adopted by the Supreme Court, which embodies long-accepted Federal law. Although forbidding the impeachment of verdicts by inquiry into the jurors’ mental processes, it deletes from the Supreme Court version the proscription against testimony “as to any matter or statement occurring during the course of the jury's deliberations.” This deletion would have the effect of opening verdicts up to challenge on the basis of what happened during the jury's internal deliberations, for example, where a juror alleged that the jury refused to follow the trial judge's instructions or that some of the jurors did not take part in deliberations.

Permitting an individual to attack a jury verdict based upon the jury's internal deliberations has long been recognized as unwise by the Supreme Court. In McDonald v. Pless, the Court stated:

* * * * *

[L]et it once be established that verdicts solemnly made and publicly returned into court can be attacked and set aside on the testimony of those who took part in their publication and all verdicts could be, and many would be, followed by an inquiry in the hope of discovering something which might invalidate the finding. Jurors would be harassed and beset by the defeated party in an effort to secure from them evidence of facts which might establish misconduct sufficient to set aside a verdict. If evidence thus secured could be thus used, the result would be to make what was intended to be a private deliberation, the constant subject of public investigation—to the destruction of all frankness and freedom of discussion and conference [ 238 U.S. 264, at 267 (1914)].

* * * * *

As it stands then, the rule would permit the harassment of former jurors by losing parties as well as the possible exploitation of disgruntled or otherwise badly-motivated ex-jurors.

Public policy requires a finality to litigation. And common fairness requires that absolute privacy be preserved for jurors to engage in the full and free debate necessary to the attainment of just verdicts. Jurors will not be able to function effectively if their deliberations are to be scrutinized in post-trial litigation. In the interest of protecting the jury system and the citizens who make it work, rule 606 should not permit any inquiry into the internal deliberations of the jurors.

Notes of Conference Committee, House Report No. 93–1597

Rule 606(b) deals with juror testimony in an inquiry into the validity of a verdict or indictment. The House bill provides that a juror cannot testify about his mental processes or about the effect of anything upon his or another juror's mind as influencing him to assent to or dissent from a verdict or indictment. Thus, the House bill allows a juror to testify about objective matters occurring during the jury's deliberation, such as the misconduct of another juror or the reaching of a quotient verdict. The Senate bill does not permit juror testimony about any matter or statement occurring during the course of the jury's deliberations. The Senate bill does provide, however, that a juror may testify on the question whether extraneous prejudicial information was improperly brought to the jury's attention and on the question whether any outside influence was improperly brought to bear on any juror.

The Conference adopts the Senate amendment. The Conferees believe that jurors should be encouraged to be conscientious in promptly reporting to the court misconduct that occurs during jury deliberations.

Notes of Advisory Committee on Rules—1987 Amendment

The amendments are technical. No substantive change is intended.

Committee Notes on Rules—2006 Amendment

Rule 606(b) has been amended to provide that juror testimony may be used to prove that the verdict reported was the result of a mistake in entering the verdict on the verdict form. The amendment responds to a divergence between the text of the Rule and the case law that has established an exception for proof of clerical errors. See, e.g., Plummer v. Springfield Term. Ry., 5 F.3d 1, 3 (1st Cir. 1993) (“A number of circuits hold, and we agree, that juror testimony regarding an alleged clerical error, such as announcing a verdict different than that agreed upon, does not challenge the validity of the verdict or the deliberation of mental processes, and therefore is not subject to Rule 606(b).”); Teevee Toons, Inc., v. MP3.Com, Inc., 148 F.Supp.2d 276, 278 (S.D.N.Y. 2001) (noting that Rule 606(b) has been silent regarding inquiries designed to confirm the accuracy of a verdict).

In adopting the exception for proof of mistakes in entering the verdict on the verdict form, the amendment specifically rejects the broader exception, adopted by some courts, permitting the use of juror testimony to prove that the jurors were operating under a misunderstanding about the consequences of the result that they agreed upon. See, e.g., Attridge v. Cencorp Div. of Dover Techs. Int'l, Inc., 836 F.2d 113, 116 (2d Cir. 1987); Eastridge Development Co., v. Halpert Associates, Inc., 853 F.2d 772 (10th Cir. 1988). The broader exception is rejected because an inquiry into whether the jury misunderstood or misapplied an instruction goes to the jurors’ mental processes underlying the verdict, rather than the verdict's accuracy in capturing what the jurors had agreed upon. See, e.g., Karl v. Burlington Northern R.R., 880 F.2d 68, 74 (8th Cir. 1989) (error to receive juror testimony on whether verdict was the result of jurors’ misunderstanding of instructions: “The jurors did not state that the figure written by the foreman was different from that which they agreed upon, but indicated that the figure the foreman wrote down was intended to be a net figure, not a gross figure. Receiving such statements violates Rule 606(b) because the testimony relates to how the jury interpreted the court's instructions, and concerns the jurors’ ‘mental processes,’ which is forbidden by the rule.”); Robles v. Exxon Corp., 862 F.2d 1201, 1208 (5th Cir. 1989) (“the alleged error here goes to the substance of what the jury was asked to decide, necessarily implicating the jury's mental processes insofar as it questions the jury's understanding of the court's instructions and application of those instructions to the facts of the case”). Thus, the exception established by the amendment is limited to cases such as “where the jury foreperson wrote down, in response to an interrogatory, a number different from that agreed upon by the jury, or mistakenly stated that the defendant was ‘guilty’ when the jury had actually agreed that the defendant was not guilty.” Id.

It should be noted that the possibility of errors in the verdict form will be reduced substantially by polling the jury. Rule 606(b) does not, of course, prevent this precaution. See 8 C. Wigmore, Evidence, §2350 at 691 (McNaughten ed. 1961) (noting that the reasons for the rule barring juror testimony, “namely, the dangers of uncertainty and of tampering with the jurors to procure testimony, disappear in large part if such investigation as may be desired is made by the judge and takes place before the jurors’ discharge and separation”) (emphasis in original). Errors that come to light after polling the jury “may be corrected on the spot, or the jury may be sent out to continue deliberations, or, if necessary, a new trial may be ordered.” C. Mueller & L. Kirkpatrick, Evidence Under the Rules at 671 (2d ed. 1999) (citing Sincox v. United States, 571 F.2d 876, 878–79 (5th Cir. 1978)).

Changes Made After Publication and Comments. Based on public comment, the exception established in the amendment was changed from one permitting proof of a “clerical mistake” to one permitting proof that the verdict resulted from a mistake in entering the verdict onto the verdict form. The Committee Note was modified to accord with the change in the text.

Amendment by Public Law

1975 —Subd. (b). Pub. L. 94–149 substituted “which” for “what” in last sentence.

Committee Notes on Rules—2011 Amendment

The language of Rule 606 has been amended as part of the restyling of the Evidence Rules to make them more easily understood and to make style and terminology consistent throughout the rules. These changes are intended to be stylistic only. There is no intent to change any result in any ruling on evidence admissibility.