In Carmell v. Texas, 529 U.S. 513 (2000), the court analyzed whether applying an amended Texas statute to the defendant violated the fourth Calder category. The defendant was charged with a sexual offense, and the prior version of the Texas statute required corroboration of the testimony of a victim of a sexual offense if the victim was 14 years old or older at the time of the offense. The statute was amended, after the dates of some of the alleged offenses, to require corroboration only where the victim was 18 years old or older at the time of the offense. The victim in Carmell was over 14 but under 18 at the time of that set of offenses, and there was no corroboration as to those alleged offenses. The Carmell majority recognized that "'the critical question for an ex post facto violation is whether the law changes the legal consequences of acts completed before its effective date.' (Carmell, 529 U.S. at p. 520 120 S. Ct. at p. 1626.) The majority found that the amendment reduced the amount of evidence needed for a finding of guilt, and concluded that if a prosecutor's case at the time of the commission of the offense would have been insufficient and the defendant would be entitled to an acquittal on the evidence, a change in the rules following the alleged commission of the offense to allow less evidence to convict the defendant violates ex post facto principles. (Id. at p. 120 S. Ct. at p. 1631.) The Texas legislature had eliminated an "outcry or corroboration" requirement for proving sexual offenses against older minors. Before the legislative change, a victim's testimony about a sexual offense generally could not support a conviction unless corroborated by other evidence or the victim had informed another person of the offense within six months of its occurrence; if the victim was younger than 14, however, the victim's testimony alone could be sufficient. After the defendant in Carmell committed offenses against a minor older than 14, the Texas legislature eliminated the requirement of outcry or corroboration for all minors, thus making the minor's testimony sufficient by itself to support a conviction. (Carmell, supra, 529 U.S. at pp. 516-519.) Challenging his conviction under the new law in the absence of outcry or corroboration evidence, the defendant asserted the new law's application against him violated the Constitution's ex post facto prohibition. The United States Supreme Court agreed. The Supreme Court explained: "The Texas statute is unquestionably a law 'that alters the legal rules of evidence, and receives less, or different, testimony, than the law required at the time of the commission of the offence, in order to convict the offender.' Under the law in effect at the time the acts were committed, the prosecution's case was legally insufficient and petitioner was entitled to a judgment of acquittal, unless the State could produce both the victim's testimony and corroborative evidence. The amended law, however, changed the quantum of evidence necessary to sustain a conviction; under the new law, petitioner could be (and was) convicted on the victim's testimony alone, without any corroborating evidence. ... Requiring only the victim's testimony to convict, rather than the victim's testimony plus other corroborating evidence is surely 'less testimony required to convict' in any straightforward sense of those words." (Carmell, supra, 529 U.S. at p. 530) The court's holding is most persuasively read as limiting the fourth category to those changes in the rules of evidence that have the practical effect of lowering the "'quantity or the degree of proof'" required to convict (Carmell, supra, 529 U.S. at pp. 543-544) In other words, evidentiary changes that reduce the legal sufficiency of the evidence necessary for a finding of guilt. "In particular, the elements of unfairness and injustice in subverting the presumption of innocence are directly implicated by rules lowering the quantum of evidence required to convict." (Carmell, at p. 546.) At the time of certain alleged sexual offenses, the law required both the victim's testimony and other corroborating evidence in order for defendant to be convicted. By the time of trial, however, the law had been amended to authorize conviction based on the victim's testimony alone. (Id. at pp. 516-520.) Holding that application of the new law to those offenses violated the ex post facto clause, the Supreme Court explained, "Under the law in effect at the time the acts were committed, the prosecution's case was legally insufficient and petitioner was entitled to a judgment of acquittal, unless the State could produce both the victim's testimony and corroborative evidence. The amended law, however, changed the quantum of evidence necessary to sustain a conviction; under the new law, petitioner could be (and was) convicted on the victim's testimony alone, without any corroborating evidence." (Id. at p. 530.) The United States Supreme Court concluded that a state statute retroactively changing the quantum of evidence necessary to sustain a conviction implicated the ex post facto clause. ( Id., at p. 530 120 S. Ct. at p. 1631.) The Carmell court stated that the proscription against ex post facto laws falls into four categories of laws: "1st. Every law that makes an action done before the passing of the law, and which was innocent when done, criminal; and punishes such action. 2d. Every law that aggravates a crime, or makes it greater than it was, when committed. 3d. Every law that changes the punishment, and inflicts a greater punishment, than the law annexed to the crime, when committed. 4th. Every law that alters the legal rules of evidence, and receives less, or different, testimony, than the law required at the time of the commission of the offence, in order to convict the offender.' " (Carmell, supra, 529 U.S. at p.522 120 S. Ct. at p. 1627.) There, a Texas statute was enacted after the offense and permitted convictions for child sexual assaults based on the victim's testimony alone. The earlier statute provided that the victim's testimony would not support a conviction unless (1) the victim's testimony was corroborated by other evidence, or (2) the victim informed another person of the offense (an "outcry") within six months of its occurrence. ( Id., at p. 517 120 S. Ct. at pp. 1624-1625.) The United States Supreme Court held that the statute violated ex post facto clause principles. (Carmell, supra, at p. 531 120 S. Ct. at p. 1632.) "A law reducing the quantum of evidence required to convict an offender is as grossly unfair as, say, retrospectively eliminating an element of the offense, increasing the punishment for an existing offense, or lowering the burden of proof . In each of these instances, the government subverts the presumption of innocence by reducing the number of elements it must prove to overcome that presumption . . ." ( Id., at p. 532 120 S. Ct. at pp. 1632-1633.) The statutory amendments effectively changed and reduced the nature and quantum of evidence needed to convict the defendant of the offense. However, the Carmell plurality recognized that, insofar as those changed standards occurring after the statutory amendments became effective, there is no ex post facto violation because the statute did not change the legal consequences of acts completed before its effective date. ( Id., at pp. 519-520.) The Court held that a state statute changing the quantum of evidence necessary to sustain a conviction violated the ex post facto clause. ( Id. at p. 530.) The Texas statute at issue in Carmell was enacted after the offense was committed and permitted convictions for child sexual assaults based on the victim's testimony alone. The earlier statute, also known as an "outcry statute" provided that the victim's testimony would not support a conviction unless (1) the victim's testimony was corroborated by other evidence, or (2) the victim informed another person of the offense within six months of its occurrence. ( Id. at p. 517.) The Supreme Court reviewed a 1993 change in Texas law pertaining to rape cases. Under prior law, a defendant could not be convicted of rape based solely upon a victim's uncorroborated testimony unless the victim had reported the rape to another person within six months of the offense. The statute had an exception to this "outcry or corroboration" requirement if the victim was under age 14. In 1993, Texas deleted this requirement for all victims, and the court in Carmell concluded this change could not be applied to crimes committed before the effective date of the statutory change. ( Id. at pp. 517-518.) It reaffirmed that procedural rule changes, such as changes in the rules of evidence, ordinarily do not implicate ex post facto concerns, but it explained that changes which alters " 'the legal rules of evidence, and receives less, or different, testimony, than the law required at the time of the commission of the offense, in order to convict the offender' " (id. at p. 522) do implicate ex post facto concerns. The court found the Texas amendment had the effect of changing the quantum of proof necessary for the prosecution to prove rape because, prior thereto, the prosecution had to demonstrate outcry or corroboration, in addition to the listed elements of rape, to sustain a conviction, while elimination of that requirement eased the prosecution's burden for proving rape. ( Id. at pp. 518-540.) The court noted, "The issue of the admissibility of evidence is simply different from the question whether the properly admitted evidence is sufficient to convict the defendant. Evidence admissibility rules do not go to the general issue of guilt, nor to whether a conviction, as a matter of law, may be sustained. Prosecutors may satisfy all the requirements of any number of witness competency rules, but this says absolutely nothing about whether they have introduced a quantum of evidence sufficient to convict the offender. Sufficiency of the evidence rules (by definition) do just that -- they inform us whether the evidence introduced is sufficient to convict as a matter of law (which is not to say the jury must convict, but only that, as a matter of law, the case may be submitted to the jury and the jury may convict). In the words of the Texas statute, 'a conviction . . . is supportable' when its requirements are met." ( Id. at p. 547.)