I dissent.
In this cause, as in many others, the analysis required of the reviewing court entails consideration of whether the trial court erred and, if so, whether its error was reversible.
Because the majority do not resolve either question correctly, I cannot join in their opinion.
I
By information filed in the Superior Court of Los Angeles County on behalf of the People, the district attorney charged that appellant Scott Breverman murdered Andreas Suryaatmadja—to quote, Breverman “did willfully, unlawfully, and with malice aforethought murder . . . Suryaatmadja, a human being”—and alleged that he did so by personally using a firearm.
Trial was by jury. In essence, the evidence showed that, one night, Breverman, a White man, was visited at this house in Chatsworth by some friends; although his own role was unclear, it was indeed clear that about eight of his friends set upon Hyun Kim and Yoon Ju, two teenage Asian-American boys, as they were walking past his house; claiming affiliation with a local street gang, they called Kim and Ju “Chinks,” “Nips,” and other racial slurs, beat them with fists and feet and weapons, and finally let them *180go; the next night, Kim returned to challenge his assailants to a fair fight, and brought along seven or eight of his friends, who were also teenage Asian-American boys, to back him up; his friends included Suryaatmadja, who was sixteen years old; finding no one in front of the house, Kim slashed one of the tires of a silver-blue BMW automobile parked in the driveway, which happened to belong to Breverman; he and his friends began to withdraw; Breverman came out of the house to check the vehicle; Kim and his friends sharply challenged Breverman to bring his friends out for a fair fight; Breverman activated the vehicle’s alarm system, and went back into the house; Kim and his friends then left; some minutes later they returned, intent on vandalizing the vehicle; although Suryaatmadja and some of the other boys apparently hung back, the rest, with hostile shouts, started battering the vehicle with various instruments; the alarm sounded; from within the house, Breverman commenced firing at Kim and his friends, using a 9-millimeter semiautomatic pistol that was not lawfully registered, shooting off four rounds; the boys fled; leaving the house, and drawing near to the vehicle, he continued firing, with his arm in a level, locked position, parallel to the ground, and finally stopped, shooting off an additional ten rounds all told; in the process, he apparently reloaded the weapon, since he shot off more rounds than its magazine could hold, and still had two remaining, one in the magazine and one in the chamber; about one-hundred and eighty-two feet away, Suryaatmadja lay mortally wounded, shot through the head.
The superior court ruled that the evidence was insufficient for first degree murder, which requires the unlawful killing of a human being with malice aforethought plus premeditation and deliberation. It proceeded to instruct the jury on murder, including second degree murder, which requires only an unlawful killing with malice aforethought. It also instructed on manslaughter, purportedly as a lesser offense necessarily included within the greater charged offense of murder, including voluntary manslaughter. In doing so, it instructed on voluntary manslaughter via the doctrine of “imperfect self-defense,” but not, in statutory terms, “upon a sudden quarrel or heat of passion” (Pen. Code, § 192, subd. (a)). It instructed as well on personal use of a firearm.
The jury returned a verdict finding Breverman guilty of second degree murder, and also finding that he personally used a firearm therein.
The superior court rendered judgment accordingly, sentencing Breverman to prison for 18 years to life—15 years to life for second degree murder, plus 3 years for personal use of a firearm.
The Court of Appeal reversed. All of the justices concluded that the superior court erred by failing to instruct the jury on voluntary manslaughter *181on a sudden quarrel or heat of passion in addition to voluntary manslaughter via imperfect self-defense, reasoning in effect that manslaughter was a lesser offense necessarily included within the greater charged offense of murder; they also concluded that the error was, as such an error generally is, “reversible per se” under People v. Sedeno (1974) 10 Cal.3d 703 [112 Cal.Rptr. 1, 518 P.2d 913]. One of the justices wrote separately to urge our reconsideration of decisions bearing on each question.
II
The majority initially conclude that the superior court erred under California law by failing- to instruct the jury on voluntary manslaughter on a sudden quarrel or heat of passion in addition to voluntary manslaughter via imperfect self-defense. In so concluding, their major premise is that a trial court must instruct sua sponte on a lesser offense necessarily included within a greater, charged offense. Their minor premise is that manslaughter is a lesser offense necessarily included within the greater charged offense of murder. We need not consider whether the major premise is sound. (But see dis. opn. of Brown, J., post, at pp. 195-202.) That is because.the minor premise is not.
It was only relatively recently that we adopted the rule that a trial court must instruct the jury sua sponte on a lesser offense necessarily included within a greater charged offense. (People v. Hood (1969) 1 Cal.3d 444, 449-450 [82 Cal.Rptr. 618, 462 P.2d 370].) Traditionally, a court was not required to give such an instruction. (5 Witkin & Epstein, Cal. Criminal Law (2d ed. 1989) Trial, § 2926, p. 3587; see People v. Hood, supra, 1 Cal.3d at p. 450 [citing decisions]; People v. Cooper (1968) 268 Cal.App.2d 34, 36-37 [73 Cal.Rptr. 608] [same]; People v. Roth (1964) 228 Cal.App.2d 522, 528-529 & fn. 2 [39 Cal.Rptr. 582] [same].)
The purpose of the rule is prophylactic, specifically, to avoid the harm of “over-conviction” and “over-acquittal.” (See, e.g., People v. Barton (1995) 12 Cal.4th 186, 195 [47 Cal.Rptr.2d 569, 906 P.2d 531].) That is to say, it aims to prevent the jury from finding the defendant guilty of a greater offense, even though he is guilty only of a lesser one, out of a desire to keep him from going unpunished. (See, e.g., ibid.) At the same time, it aims to prevent the jury from finding the defendant not guilty of a greater offense and letting him go unpunished, even though he is, in fact, guilty of a lesser one. (See, e.g., ibid.)
By its very terms, however, the rule is limited. A trial court must instruct sua sponte when, and only when, the lesser offense is necessarily included *182within the greater charged offense. Two standards are applicable. (E.g., People v. Wolcott (1983) 34 Cal.3d 92, 98 [192 Cal.Rptr. 748, 665 P.2d 520]; People v. Wright (1996) 52 Cal.App.4th 203, 208 [59 Cal.Rptr.2d 316].) Under the so-called “legal elements” test (People v. Wright, supra, 52 Cal.App.4th at p. 208), the lesser is necessarily included within the greater if, as a matter of law in view of their respective statutory definitions, an actor cannot commit the greater without necessarily committing the lesser (People v. Wolcott, supra, 34 Cal.3d at p. 98; People v. Wright, supra, 52 Cal.App.4th at p. 208). Under the so-called “accusatory pleading” test (People v. Wright, supra, 52 Cal.App.4th at p. 208), the lesser is necessarily included within the greater if, as a matter of fact in view of the allegations describing his conduct, an actor cannot commit the greater without necessarily committing the lesser (People v. Wolcott, supra, 34 Cal.3d at p. 98; People v. Wright, supra, 52 Cal.App.4th at p. 208).
Under neither the legal elements test nor the accusatory pleading test is the lesser offense of manslaughter necessarily included within the greater charged offense of murder.
Originally, murder was defined by statute as the “unlawful killing of a human being, with malice aforethought.” (Pen. Code, § 187 (1872).) For its part, manslaughter was similarly defined as the “unlawful killing of a human being, without malice.” (Id., § 192 (1872).)
In 1970, murder was expanded in its statutory definition to include the “unlawful killing of a human being, or a fetus, with malice aforethought.” (Pen. Code, § 187, subd. (a), as amended by Stats. 1970, ch. 1311, § 1, p. 2440, italics added.)
Neither in that year nor thereafter was manslaughter expanded in its statutory definition to include the unlawful killing of a fetus without malice aforethought. Indeed, just months ago, we held that manslaughter excluded a fetus as a victim. (People v. Dennis (1998) 17 Cal.4th 468, 505-506 [71 Cal.Rptr.2d 680, 950 P.2d 1035].)
Moreover, even though murder is statutorily defined as an unlawful killing with malice aforethought and manslaughter is similarly defined as an unlawful killing without malice aforethought, as currently understood (see, e.g., People v. Barton, supra, 12 Cal.4th at pp. 199-201), they are not distinguished simply by their contradictory prepositions. True, it appears that murder is marked by the presence of malice aforethought, and manslaughter by its absence. But the “absence” of malice aforethought in manslaughter is not, strictly speaking, the absence of malice aforethought but rather the *183presence of other, extrinsic “circumstances” (id. at p. 199), specifically, for voluntary manslaughter, a sudden quarrel or heat of passion or imperfect self-defense (ibid.; see maj. opn., ante, at p. 153; see generally, dis. opn. of Kennard, J., post, at pp. 188-189; see also id. at p. 189, fn. 4 [stating that “voluntary manslaughter might be termed a lesser including offense of murder” (original italics)]).
Under the legal elements test, the lesser offense of manslaughter is not necessarily included within the greater charged offense of murder. That is because, as a matter of law in view of their respective statutory definitions, an actor can indeed commit murder without necessarily committing manslaughter. Put otherwise: It is not the case that an actor cannot commit murder without necessarily committing manslaughter. Such a person can assuredly commit murder under circumstances devoid of sudden quarrel or heat of passion or imperfect self-defense. He can also do so against a fetus. If he commits murder under such circumstances or against such a victim, it does not follow that he necessarily commits manslaughter. To the contrary, it follows that he necessarily does not do so.
Likewise, under the accusatory pleading test, the lesser offense of manslaughter is not necessarily included within the greater charged offense of murder. That is because, as" a matter of fact in view of the allegations describing his conduct, an actor can indeed commit murder without necessarily committing manslaughter. In pertinent part, the information filed below charged only that Breverman “did willfully, unlawfully, and with malice aforethought murder . . . Suryaatmadja, a human being.” It is not the case that an actor who so conducts himself cannot commit murder without necessarily committing manslaughter. Quite the opposite. Such a person commits murder under circumstances devoid of sudden quarrel or heat of passion or imperfect self-defense. It follows that he necessarily does not commit manslaughter. Contrary to the majority’s implication (see maj. opn., ante, at p. 154, fn. 5), it matters not that his victim is identified as a human being rather than a fetus. To repeat: He commits murder under circumstances devoid of sudden quarrel or heat of passion or imperfect self-defense.
All this is not to deny that manslaughter, as currently understood, is a lesser offense related to the greater charged offense of murder. But this very day, in People v. Birks (1998) 19 Cal.4th 108 [77 Cal.Rptr.2d 848, 960 P.2d 1073], we hold that a trial court need not instruct on lesser related offenses even at the defendant’s request, and indeed generally may not do so. If we *184are to qualify that holding, we should do so deliberately. The majority do not even make an attempt.1
Ill
The majority then conclude that the superior court may have erred reversibly under California law by failing to instruct the jury on voluntary manslaughter on a sudden quarrel or heat of passion in addition to voluntary manslaughter via imperfect self-defense.
I disagree.
My first reason is this: The superior court did not err at all, reversibly or otherwise.
My second reason is different. It is suggested in the majority’s analysis, but is not developed therein. It follows.
In addressing the question of reversibility, we consider, as a general matter, whether or not the error caused prejudice, which is simply a taint on the trial in the form of an unfavorable effect on the outcome, meaning, in a jury trial, an unfavorable effect on the verdict.
To consider prejudice, we first choose the appropriate standard—such as the “harmless-beyond-a-reasonable-doubt” test (Chapman v. California (1967) 386 U.S. 18, 24 [87 S.Ct. 824, 828, 17 L.Ed.2d 705, 24 A.L.R.3d 1065]), which generally applies to error violative of the United States *185Constitution; the “reasonable-probability” test (People v. Watson (1956) 46 Cal.2d 818, 836-837 [299 P.2d 243]), which usually covers error under California law; and the “reasonable-possibility” test (People v. Brown (1988) 46 Cal.3d 432, 446-448 [250 Cal.Rptr. 604, 758 P.2d 1135]), which covers error under California law bearing on the penalty of death.
Having chosen the appropriate standard, we then ask the ultimate question of prejudice itself, using, in effect, one of two verbal formulas. We sometimes inquire—as do the majority at one point in their opinion (see maj. opn., ante, at p. 177)—whether, under the standard in question, the error had an unfavorable effect on the outcome. (See, e.g., People v. Alvarez (1996) 14 Cal.4th 155, 234 [58 Cal.Rptr.2d 385, 926 P.2d 365] [under reasonable-possibility test]; People v. Marshall (1996) 13 Cal.4th 799, 851-852 [55 Cal.Rptr.2d 347, 919 P.2d 1280] [under harmless-beyond-a-reasonable-doubt test]; People v. Gordon (1990) 50 Cal.3d 1223, 1253 [270 Cal.Rptr. 451, 792 P.2d 251] [under reasonable-probability standard]; cf. People v. Alvarez, supra, 14 Cal.4th at pp. 239, 241, fn. 38 [under reasonable-probability standard for prejudice component of ineffective assistance of counsel violative of United States Constitution, Amendment VI, and California Constitution, article I, section 15].) At other times, we inquire—as do the majority at another point in their opinion (see maj. opn., ante, at p. 178)— whether, under the standard in question, a more favorable outcome would have resulted in the absence of the error. (See, e.g., People v. Bradford (1997) 14 Cal.4th 1005, 1061 [60 Cal.Rptr.2d 225, 929 P.2d 544] [under harmless-beyond-a-reasonable-doubt test]; People v. Jackson (1996) 13 Cal.4th 1164, 1211 [56 Cal.Rptr.2d 49, 920 P.2d 1254] [under reasonable-probability test]; People v. Wader (1993) 5 Cal.4th 610, 666 [20 Cal.Rptr.2d 788, 854 P.2d 80] [under reasonable-possibility test]; cf. People v. Ledesma (1987) 43 Cal.3d 171, 217-218 [233 Cal.Rptr. 404, 729 P.2d 839] [under reasonable-probability standard for prejudice component of ineffective assistance of counsel violative of United States Constitution, Amendment VI, and California Constitution, article I, section 15].)
Whether we use one or the other of the two verbal formulas is a matter of rhetorical style and makes no substantial difference—so long as we focus on the fact that prejudice is an unfavorable effect on the outcome. When we so focus, we recognize a truth that is deceptively simple: Reversal is required if the error caused prejudice, that is, an unfavorable effect on the outcome. Reversal, however, is not required merely if the absence of error would have resulted in a more favorable outcome. In the former situation, there is a taint on the trial. In the latter, there is not.
Turning to the case at bar, I believe that, even if the superior court had erred by failing to instruct on voluntary manslaughter on a sudden quarrel or *186heat of passion in addition to voluntary manslaughter via imperfect self-defense, its “error” could not have been reversible. The “error” could not have caused prejudice. That is because it could not have caused an unfavorable effect on the verdict. It could only have affected a verdict finding Breverman guilty of voluntary manslaughter—which was not returned by the jury. It could not have affected the verdict finding him guilty of second degree murder—which was.
As I have explained, the purpose of the rule requiring a trial court to instruct sua sponte on a lesser offense necessarily included within a greater charged offense is to avoid the harm of “over-conviction” and “over-acquittal.” Even if the rule had been applicable here, its purpose would not have been frustrated. Breverman was obviously not “over-acquitted” by the jury. Indeed, he was not acquitted by it at all. Neither was he “over-convicted.” Certainly, the evidence of second degree murder was more than sufficient to support its verdict under the due process clauses of the Fourteenth Amendment to the United States Constitution and article I, section 15 of the California Constitution. Viewing the evidence in the light most favorable to the People, a rational jury could surely have found all that it had to find beyond a reasonable doubt, namely, that Breverman unlawfully killed Suryaatmadja with malice aforethought. (See, e.g., People v. Rowland (1992) 4 Cal.4th 238, 269 [14 Cal.Rptr.2d 377, 841 P.2d 897].)
In sum, and unlike the majority (see maj. opn., ante, at p. 178, fn. 25), I am compelled to conclude that the jury’s verdict finding Breverman guilty of second degree murder—a verdict that was returned after an untainted trial, and that was supported by more than sufficient evidence—did not, and could not, amount to, or reflect, a “miscarriage of justice,” either under article VI, section 13 of the California Constitution or otherwise.2
IV
For the reasons stated above, I would reverse the judgment of the Court of Appeal and remand the cause to that court without directions to reconsider the question of reversibility.
I note in passing that, by instructing on voluntary manslaughter via imperfect self-defense, the superior court effectively instructed on voluntary manslaughter on a sudden quarrel or heat of passion. Common to both was Breverman’s reaction to Kim and his friends, including Suryaatmadja. Voluntary manslaughter on a sudden quarrel or heat of passion requires provocation that is adequate to arouse a reasonable person. (E.g., People v. Valentine (1946) 28 Cal.2d 121, 136-144 [169 P.2d 1].) So aroused, such a person may act in terror (e.g., People v. Logan (1917) 175 Cal. 45, 49 [164 P. 1121]), but not for revenge (e.g., ibid.)—not even against teenage boys of a different ethnic group who vandalize his expensive automobile. Here, Breverman’s emotions doubtless ran high. But even if they began in terror, they evidently ended in revenge, as he shot off his last rounds, standing near his BMW, with his arm in a level, locked position, parallel to the ground. The same evidence that assertedly supported voluntary manslaughter via imperfect self-defense assertedly supported voluntary manslaughter on a sudden quarrel or heat of passion. That evidence, of course, was rejected by the jury, not at all unreasonably.
Unlike Justice Kennard, I decline to consider, in detail and in depth, the relationship between murder and manslaughter and their respective statutory definitions. I do so because the parties did not raise the issue in the Court of Appeal. (See Cal. Rules of Court, rule 29(b)(1).) The question is surely an important one. But it will not escape examination. It is implicated in People v. Lee, review granted May 21, 1997 (S060352), which is currently pending on review.*
Reporter’s Note: For Supreme Court opinion see 20 Cal.4th 47.
Against my conclusion, it might be argued that a trial court’s error in failing to instruct on a lesser offense necessarily included within a greater charged offense would be “nomreversible per se” whenever the jury does not “over-convict” or “over-acquit.” But if the harm that such a failure threatens, which is, of course, “over-conviction” and “over-acquittal,” does not come to pass, there is no ground for reversal. In this situation, the trial court, by failing to instruct as indicated above, may have failed to provide prophylaxis—but prophylaxis proved not to be necessary.
Unlike Justice Kennard, I decline to consider, in any way, the relationship between murder and manslaughter and its consequences under the United States Constitution. I do so because the parties did not raise the issue in the Court of Appeal. (See, ante, at p. 184, fn. 1.)