¶1OPINION
¶2delivered the opinion of the Court,
¶3The question presented is whether the Fifth Court of Appeals erred in holding *32that the trial court erred in its instructions to the jury at the punishment stage of trial. We hold that the Court of Appeals did not err.
¶4The Relevant Facts
¶5A Dallas County grand jury indicted appellant, Mary Lucia Sanchez, for the murder of Judy Lynn Green. See Tex. Pen.Code § 19.02(b)(1) & (2). The case went to trial before a jury. At the guilt/innocence stage of trial, the State presented evidence that on the evening of October 2, 1996, appellant shot and killed Green, her former lover, in Green’s home in Dallas. The State’s evidence included a written statement appellant gave to police shortly after the shooting. In the statement, appellant admitted shooting Green but claimed she did so only after Green attacked her:
She ... had me by the neck. I felt stinging, I thought, from her rings or fingernails. I got mad because she was being cruel. I reached out and got the gun [which Green kept on a night stand]. I pushed her toward the door and I just shot. She came at me and we fought over the gun. It went off and I felt a burning sensation in my leg.[1] I was so mad, I started pulling the trigger.
¶6Appellant took the witness stand in her defense and testified that she shot Green because she believed Green was trying to kill her. The jury rejected appellant’s claim of self-defense and found her guilty of murder, as charged in the indictment.
¶7At the punishment stage of trial, appellant attempted to prove that she shot Green under the immediate influence of sudden passion arising from an adequate cause, which would reduce her offense from a first-degree felony to a second-degree felony
¶8The trial court instructed the jurors that they could find in appellant’s favor on the issue of sudden passion only if they were unanimous, and that otherwise they would have to find against appellant on the issue. After deliberating, the jurors assessed appellant’s punishment at imprisonment for twenty-five years, a punishment beyond the maximum allowed for a second-degree felony. See footnote three, supra. When asked by the trial court whether their decision was unanimous, the jurors answered that it was not. Three jurors wanted to find in appellant’s favor on the issue of sudden passion, but because of the trial court’s instructions, they had to find against appellant on the issue.
¶9On direct appeal, appellant argued, for the first time, that the trial court fundamentally erred in its instructions to the jury on the issue of sudden passion. Appellant argued that the trial court’s instructions allowed the jury to return a non-unanimous decision adverse to her, and that Texas Constitution article V, § 13, requires that jury decisions adverse *33to a defendant be unanimous. See Molandes v. State, 571 S.W.2d 3, 4 (Tex.Crim.App.1978). Appellant also argued that the trial court’s error caused her egregious harm, “demonstrated by the fact that the jury assessed 25 years where the statutory maximum for a second-degree felony is 20 years.”
¶10The Fifth Court of Appeals agreed -with appellant that the trial court fundamentally erred in its punishment charge, but the Court of Appeals did not reach appellant’s constitutional claim, preferring instead to decide the point of error on the basis of Article 37.07, § 3(c), of the Texas Code of Criminal Procedure:
¶11Article 37.07 [§ 3(c) ] provides that:
In cases where the matter of punishment is referred to the jury, the verdict shall not be complete until the jury has rendered a verdict on the guilt or innocence of the defendant and the amount of punishment, where the jury finds the defendant guilty. In the event the jury shall fail to agree, a mistrial shall be declared, the jury shall be discharged, and no jeopardy shall attach.
([Ejmphasis added.) Thus, by its express language, section [sic] 37.07 requires the jury to “agree” on punishment. To “agree” on punishment means a unanimous vote. The special issue on sudden passion determines the applicable punishment range. We discern no significant distinction between “punishment” and “punishment range.” Thus, we conclude that if the jury’s answer is not unanimous on the issue of sudden passion, the jury has not “agreed” on punishment. To allow a charge such as the one given in this case would, in theory, allow a single juror to determine the range of punishment. We conclude that such a proposition is without any basis in law.
¶12Sanchez v. State, No. 05-97-01389, slip. op. at 12-14, 1999 WL 173986 (Tex.App. — Dallas 1999) (not designated for publication) (emphasis in original; citations and some punctuation omitted). Having determined that the trial court’s charge on punishment was erroneous, the Court of Appeals went on to hold that the error caused appellant egregious harm, requiring reversal of the trial court’s judgment with respect to punishment and a new punishment hearing. Ibid.See Almanza v. State, 686 S.W.2d 157, 171 (Tex.Crim.App.1985); Tex.Code Crim. Proc. art. 44.29(b).
¶13We subsequently granted the State’s petition for discretionary review to determine whether the Court of Appeals erred in concluding that the trial court erred in its punishment charge. See Tex.R.App. Proc. 66.3(b). In its brief to this Court, the State argues that Article 37.07, § 3(c), requires jury unanimity with respect to the “amount of punishment” ultimately assessed, but not with respect to the jury’s preliminary vote on the issue of sudden passion.
¶14Analysis
¶15The trial court’s punishment charge allowed the jury to return a non-unanimous decision adverse to appellant on the issue of sudden passion. We must determine whether allowing the jury to do that conflicted with Article 37.07, § 3(c).
¶16Article 37.07, § 3(c), which became effective January 1,1966, requires the jury to “agree,” ie., agree unanimously, on “the guilt or innocence of the defendant and the amount of punishment, where the jury finds the defendant guilty.” If the jury does not agree unanimously, then the trial court must declare a mistrial. See Henderson v. State, 593 S.W.2d 954, 956 (Tex.Crim.App.1980); Stanton v. State, 535 S.W.2d 182, 183 (Tex.Crim.App.1976); Brown v. State, 508 S.W.2d 91, 93 (Tex. Crim.App.1974); see also Tex.Code Crim. Proc. art. 36.29(a) (requiring jury unanimity on all felony verdicts). The evident purpose of the statute is to ensure that thorough jury deliberation does not cease once a simple majority is achieved, thereby increasing the reliability of the verdicts *34ultimately reached. See United States v. Lopez, 581 F.2d 1338, 1341 (9th Cir.1978).
¶17Before September 1, 1994, the existence of sudden passion was an element of the offense of voluntary manslaughter (a lesser-included offense of murder), to be determined by the jury at the guilVinnocence stage. See Bradley v. State, 688 S.W.2d 847, 849 (Tex.Crim.App.1985) (plurality op.). Effective September 1, 1994, the existence of sudden passion became a punishment stage issue. See footnote two, supra. Article 37.07, § 3(c), however, was left unchanged in 1994, and it is now unclear whether that statute applies to a jury’s preliminary vote on sudden passion.
¶18When we interpret statutes, we seek always to effectuate the collective legislative intent or purpose. Boykin v. State, 818 S.W.2d 782, 785-786 (Tex.Crim.App.1991). When we interpret ambiguous statutes like Article 37.07, § 3(c), we may, in seeking a proper interpretation, consider extratextual factors. Ibid. Consideration of two such factors leads us to conclude that Article 37.07, § 3(c), requires unanimity with respect to the jury’s preliminary vote on sudden passion.
¶19First, we think the evident purpose of the statute — to increase the reliability of jury verdicts — is best achieved if the statute is interpreted to apply to the jury’s preliminary vote on sudden passion. If the statute were interpreted not to apply, then a situation could arise in which, as in the instant case, the range of punishment is determined by less (perhaps much less) than all the jurors. In such a situation, the reliability of the punishment verdict would tend to be decreased, rather than increased, and that would be at odds with the evident purpose of the statute. Second, we think that if the Legislature intended to exempt the jury’s decision on the sudden passion issue from the statutory unanimity requirement, it would have stated its intention expressly.
¶20In summary, we agree with the Fifth Court of Appeals that the trial court erred in its punishment charge. We affirm the judgment of the Court of Appeals.
¶211. The Slate’s evidence also established that, at the time in question, appellant was shot in her left thigh.
¶22. Texas Penal Code § 19.02, the penal provision applicable to this case, provides in relevant part:
(c) Except as provided in Subsection (d), an offense under this section is a felony of the first degree.
(d) At the punishment stage of a trial, the defendant may raise the issue sis to whether he caused the death under the immediate influence of sudden passion arising from an adequate cause. If the defendant proves the issue in the affirmative by a preponderance of the evidence, the offense is a felony of the second degree.
¶23.Texas Penal Code § 12.32 provides that punishment for a first-degree felony is imprisonment for five to 99 years or life, plus a fine of up to $10,000. Texas Penal Code § 12.33 provides that punishment for a second-degree felony is imprisonment for two to twenty years, plus a fine of up to $10,000.
¶24. We note that, because the error of which appellant complains affected just the punishment phase of her trial, she is entitled only to a new punishment hearing. See Tex. Code Crim. Proc. art. 44.29(b).
¶25delivered a concurring opinion in which KEASLER, J. joined.
¶26At the punishment stage of trial, the trial court instructed the jury that “[a]n affirmative (‘yes’) answer on the issue [of sudden passion] submitted must be unanimous, but if the jury is not unanimous in *36reaching an affirmative answer, then the issue must be answered ‘no.’ ”
¶27In interpreting Texas Code of Criminal Procedure, Article 37.07 § 3(c), I resort to the traditional rules of statutory construction. Texas appellate courts' interpret a statute in accordance with the plain meaning of its language unless the language is ambiguous or the plain meaning leads to absurd results.
¶28In this case, the language of Article 37.07 § 3(c) is ambiguous. The statute calls for a unanimous verdict on guilt and “the amount of punishment.”
¶29The unanimity provision was enacted into the Code of Criminal Procedure in 1967. At that time, offenses were not categorized into degrees but simply carried ranges of punishment, and in some cases, if some fact were proven, the punishment range might be increased or decreased.
¶30In searching cases involving the pre-1973 Penal Code, I can find none that address whether jury unanimity was required for a punishment issue. One explanation for this absence of relevant authority may be the fact that the bifurcated trial requirement was not imposed until 1965.
¶31At the same time the 1973 Penal Code was enacted, the Legislature also enacted Texas Code of Criminal Procedure, Article 37.071. In that Article, the Legislature set forth three punishment issues for capital cases and expressly provided that the jury - must agree unanimously on answers adverse to the defendant but could answer the issues in the defendant’s favor on ten votes or more.
¶32Despite the Legislature’s express guidance with regard to capital cases in 1973, no changes were made at that time in Article 37.07, applying to noncapital cases. But there was only one provision in the 1973 Penal Code that purported to establish a punishment issue for noncapital cases, and that issue was in fact a defensive issue. Texas Penal Code § 15.04(d) established an imperfect renunciation mitigating factor for inchoate offenses:
Evidence that the defendant renounced his criminal objective by abandoning his criminal conduct, countermanding his solicitation, or withdrawing from the conspiracy before the criminal offense was committed and made substantial effort to prevent the commission of the object offense shall be admissible as mitigation at the hearing on punishment, if he has been found guilty of criminal attempt, criminal solicitation, or criminal conspiracy; and in the event of a finding of renunciation under this subsection, the punishment shall be one grade lower than that provided for the offense committed.13
¶33Although commentators to the 1973 Penal Code have discussed this mitigating factor, they have been silent about whether jury unanimity on the issue is required.
¶34As with the issue of malice in the pre-1973 Penal Code, the “sudden passion”
¶35In 1993, the Legislature abolished the offense of voluntary manslaughter and made the sudden passion issue a punishment issue in murder cases.
¶36At any rate, absent a clear indication in the legislative history that the Legislature intended a dramatic change in unanimous verdict requirements for the offense of murder, we should be reluctant to infer from an ambiguous textual basis that the Legislature desired such a change.
¶37Further, a review of cases in other jurisdictions supports a unanimity requirement for findings adverse to the defendant on defensive punishment issues. There is currently no right to a jury trial at the punishment phase of a criminal trial in federal court.
And, finally, you will recall I said that you are instructed that before you may return a qualified verdict of murder in the first degree without capital punishment, that your decision to do so must, like your regular verdict, be unanimous.32
¶38The Supreme Court held that this instruction deprived the defendant of his right to a unanimous verdict adverse to him:
It seems to us, however, that where a jury is told first that their verdict must be unanimous, and later, in response to a question directed to the particular problem of qualified verdicts, that if their verdict is first degree murder and they desire to qualify it, they must be unanimous in so doing, the jury might reasonably conclude that, if they cannot all agree to grant mercy, the verdict of guilt must stand unqualified.33
¶39A couple of states have addressed an analogous situation involving affirmative defenses. As with the sudden passion mitigation issue, a decision on an affirmative defense is not itself a decision on the final issue in the case (i.e. guilt). And in fact, the sudden passion issue acts much like an affirmative defense in the punishment phase: just as an affirmative defense admits the crime but seeks to avoid criminal liability by showing other facts that justify the conduct, the sudden passion issue admits that the crime has occurred but seeks to avoid the full impact of the punishment by proof of other facts that mitigate against the usual penalty.
¶40In State v. Miyashiro, the jury asked the trial judge “is unanimity required in the decision of whether entrapment oc*40curred?”
¶41In State v. Harris, the Supreme Court of Rhode Island held that unanimity was required to find against the defendant on the insanity defense.
Should, however, after weighing carefully all the evidence, you should find yourselves unconvinced of the truth of the defendant’s plea, then the defendant must be deemed to have failed in his proof. In which event, the presumption of the defendant’s sanity survives and your conclusion and finding of guilt under the first plea remains unchanged. Furthermore, if you should find that the evidence for and against the defendant’s plea of insanity simply balances evenly, so that you cannot agree on a finding, the defendant must again be held to have failed in his proof, and in this event also the presumption of the defendant’s sanity survives, and, your original finding of guilt remains unchanged. Again, if after weighing the evidence carefully, though you can’t agree, there should however still remain a doubt in your minds about the defendant’s sanity, then you must find that the defendant’s plea has failed again. In which event, the presumption of his sanity survives and must prevail, and your finding of guilty under the first plea still stands. If accordingly you find that the defendant’s plea of insanity has failed of sufficient proof and that you cannot agree or that you cannot agree upon a finding or that all you have about it is a doubt and that, as the law requires, the presumption of his sanity survives and prevails, you will thereupon return to the Court as your verdict a finding you have made under the first plea.39
¶42The Supreme Court of Rhode Island quoted Andres for the proposition that all issues decided by a jury must be decided unanimously.
¶43In Harris v. State, the Supreme Court of Delaware addressed whether unanimity was required for a jury finding of mercy under Delaware’s punishment scheme.
¶44*41The defendant in Harris was convicted of the crime of rape. Delaware law provided that rape would be punished as follows:
Whoever commits the crime of rape;
[[Image here]]
Shall be guilty of felony and shall suffer life imprisonment. If the jury at the time of rendering their verdict recommends the defendant to mercy, the court may impose a sentence for any period not less than 3 years, instead of life imprisonment.43
¶45The jury unanimously delivered a verdict of guilt, but was unable to agree as to a recommendation of mercy.
¶46The Supreme Court of Delaware affirmed the conviction. The court observed that “the prevailing construction of the various statutes makes the jury’s decision on remission of punishment a constituent part of the verdict, requiring unanimous jury action one way or the other on that issue, along with a verdict of guilt.”
¶47Unlike the mercy statutes in Delaware, the sudden passion issue in Texas is a constituent part of the punishment verdict. In this regard, the sudden passion issue shares more in common with the affirmative defense statutes discussed by the Hawaii and Rhode Island courts, and with the punishment statute discussed by the Supreme Court in Andres.
¶48Finally, when a statute is ambiguous, we should interpret it to avoid serious constitutional concerns.
¶49*42With these comments, I concur in the Court’s judgment.
¶50. Sanchez v. State, No. 05-97-01389-CR, slip op. at 12, 1999 WL 173986 (Tex.App. — Dallas, March 31, 1999)(unpublished)(bracketed material in Court of Appeals’ opinion).
¶51. Boykin v. State, 818 S.W.2d 782, 785-786 & 786 n. 4 (Tex.Crim.App.1991).
¶52. Tex. Gov’t.Code, § 311.023; Brown v. State, 943 S.W.2d 35, 38 (Tex.Crim.App.1997).
¶53. See Article 37.07 § 3(c).
¶54. See generally Texas Penal Code of 1948 and supplements through 1967.
¶55. Texas Penal Code, Articles 1256 and 1257b (1948); Mims v. State, 3 S.W.3d 923, 926 (Tex.Crim.App.1999).
¶56. Carver v. State, 510 S.W.2d 349, 354 (Tex.Crim.App.1974); see also Smith v. State, 5 S.W.3d 673, 684 (Tex.Crim.App.1999)(Keller, J. concurring and dissenting).
¶57. All references to ‘’malice” are intended by this opinion to refer to the concept of “malice aforethought” as that term was used in the pre-1973 Penal Code.
¶58. Carver, 510 S.W.2d at 354.
¶59. See Texas Penal Code, Articles 1256 and 1257b (1948); Mims, 3 S.W.3d at 926.
¶60. Article 37.031(b) & (d) (1973).
¶61. Article 37.071 § 2(e) & (f)(1991). These provisions have remained unchanged to date except for renumbering (e) as (e)(1).
¶62. This provision has remained unchanged since 1973.
¶63. Seth S. Searcy, III and James R. Patterson, Vernon’s Annotated Penal Code, § 15.04, Practice Commentary (1974); Branch’s 3 rd Edition, Texas Annotated Penal Statutes, § 15.04, Explanatory Comment (1974).
¶65. All references to “sudden passion” are intended by this opinion to refer to "sudden passion arising from an adequate cause” as that phrase is used and defined in Texas Penal Code § 19.02(a) & (d) and its predecessors.
¶66. Texas Penal Code § 19.04(1973).
¶67. Braudrick v. State, 572 S.W.2d 709, 710-711 (Tex.Crim.App.1978), cert. denied, 440 U.S. 923, 99 S.Ct. 1252, 59 L.Ed.2d 477 (1979).
¶68. Cobarrubio v. State, 675 S.W.2d 749, 751-752 (Tex.Crim.App.1983), overruled on other grounds by, Lawrence v. State, 700 S.W.2d 208 (Tex.Crim.App.1985).
¶69. Ruiz v. State, 753 S.W.2d 681, 687 (Tex.Crim.App.1988).
¶70. Compare § 19.02(d) (current) and § 19.04(a)(1993); see Mims, 3 S.W.3d at 925.
¶71. See § 19.02(d).
¶72. Knox Fitzpatrick, Senate Criminal Justice Committee, SB 1067, April 14, 1993, Tape 2, Side 1.
¶73. House Research Organization Digest, Bill Analysis, May 6, 1993, Table B: Person Offense Rankings, p. 40 (bill analysis p. 11) and Table D: Offense Sections Deleted from Penal Code, p. 46 (bill analysis p. 17).
¶74. Mims, 3 S.W.3d at 927.
¶75. Id.
¶76. For example, under the current statute a trial court's erroneous refusal to admit evidence relevant to the sudden passion issue could result only in a new punishment hearing rather than an entire new trial.
¶77. See Fed.R.Crim.P. 32(c)(1).
¶78. Andres v. United States, 333 U.S. 740, 748, 68 S.Ct. 880, 92 L.Ed. 1055 (1948)(emphasis added). In saying that all issues resolved by the jury must be resolved unanimously, the Supreme Court did not suggest that a jury must agree on every fact submitted to it for consideration. The Supreme Court draws a distinction between the "underlying brute facts” that make up an element (or a defense) and the legal elements of a crime (or defense). Richardson v. United States, 526 U.S. 813, 119 S.Ct. 1707, 1710, 143 L.Ed.2d 985 (1999); see also Schad v. Arizona, 501 U.S. 624, 631-632, 111 S.Ct. 2491, 115 L.Ed.2d 555 (1991).
¶79. Id. at 741, 68 S.Ct. 880. The defendant was tried in United States District Court because Hawaii was a Territory at the time. Id.
¶82. Id. at 752, 68 S.Ct. 880; see also id. at 751, 68 S.Ct. 880.
¶83. State v. Miyashiro, 90 Hawai'i 489, 979 P.2d 85, 92 (1999).
¶87. State v. Harris, 89 R.I. 202, 152 A.2d 106 (1959).
¶91. Harris v. State, 293 A.2d 291 (Del.1972).
¶101. State v. Edmond, 933 S.W.2d 120, 124 (Tex.Crim.App.1996).
¶102. Johnson v. Louisiana, 406 U.S. 356, 359-363, 92 S.Ct. 1620, 32 L.Ed.2d 152 (1972)