(dissenting). Although our grant of leave to appeal in this case did not specify issues for consideration, the appellant framed the issues as whether the defendant’s Michigan and federal constitutional rights to speedy trial and her statu*730tory right to a trial within 180 days, MCL 780.131; MSA 28.969(1), were waived by an unconditional guilty plea. Not only does the majority fail to resolve a conflict that now exists in the Court of Appeals, it incorrectly interprets the 180-day rule and ignores the well-established rules of stare decisis. Accordingly, I would hold that this Court’s decision in People v Woodruff, 414 Mich 130; 323 NW2d 923 (1982), properly interpreted the 180-day rule to apply to a prisoner in the defendant’s circumstances. Furthermore, I would affirm the Court of Appeals decision, holding that although the defendant waived her constitutional rights to a speedy trial by her unconditional guilty plea, her claim that the 180-day rule was violated is not waived by that same plea.
I. INTERPRETATION OF MCL 780.131 ET SEQ.; MSA 28.969(1) ET SEQ.
In Woodruff, supra at 137, this Court held that the 180-day rule applied to any untried charge against an inmate even if the offense was committed in prison or carried a mandatory consecutive sentence. The Court applied a statutory rule of construction that requires penal statutes to be strictly construed, People v Goulding, 275 Mich 353; 266 NW 378 (1936); Gay v Webster, 277 Mich 255, 259; 269 NW 164 (1936), especially when such an interpretation will be beneficial to the defendant. People v Lockhart, 242 Mich 491; 219 NW 724 (1928). The majority here states that a more liberal interpretation of the 180-day rule is warranted because of a legislative amendment that occurred over six and one-half years after our decision in Woodruff. On the basis of this amendment, the majority would overturn Woodruff and find that the statute does not apply to the defen*731dant even though her plea and conviction occurred over one year before the amendment to the statute became effective. However, under the rules of statutory interpretation and the doctrine of stare decisis, the majority’s reasoning is unpersuasive.1
The majority’s use of the subsequent statutory amendment of the 180-day rule to overrule Wood-ruff can be attacked on a number of grounds. One rule of statutory construction requires that when a statute is clear and unambiguous, an amendment that materially changes the statute is presumed to indicate a change in existing legal rights. 1A Sands, Sutherland Statutory Construction (4th ed), § 22.30, p 265. The author of the lead opinion has also previously applied this rule. See Sam v Balardo, 411 Mich 405, 445; 308 NW2d 142 (1981) (Levin, J., dissenting). Even if we were to be influenced by a subsequent Legislature’s amendment of our decision in Woodruff, the Legislature, in fact, let that decision stand for over six and one-half years before changing the statute and did not even mention Woodruff in doing so. Instead, the lapse in time simply indicates that the Legislature felt that the statute should be amended for reasons other than our decision in Woodruff.2 The amendment, therefore, results in a change of existing legal rights and the Court should refrain from using the amendment to interpret the preexisting *732statute. Instead, the Court should simply apply the plain and unambiguous language of the statute, as noted in Woodruff, 414 Mich 135-136, to the present case.
The majority also, by applying the language of the new statute, in eifect applies this penal statute retroactively when the Legislature has not deemed it necessary to do so. Not only does this contravene the rule that amendments to statutes are generally inapplicable when transactions and events are completed prior to their enactment, 1A Sands, Sutherland Statutory Construction, supra, § 22.36, pp 300-301, but it also attempts to apply a statute retroactively without undertaking an analysis of whether that statute should be so applied. See People v Hampton, 384 Mich 669; 187 NW2d 404 (1971). The amendments here should not be applied retroactively. Their purpose was to change the law, not to clarify what the statute meant. The Legislature did not deem it appropriate to apply the amendments retroactively, and this Court should not attempt to legislate such a change by its opinion.
The doctrine of stare decisis also requires this Court to uphold Woodruff This doctrine exists to promote uniformity, certainty, and stability in the law, Parker v Port Huron Hosp, 361 Mich 1, 10; 105 NW2d 1 (1960), and when a court of competent jurisdiction decides a case, that decision becomes precedent which should not be lightly overturned. People v Jamieson, 436 Mich 61, 79; 461 NW2d 884 (1990). Under the doctrine of stare decisis, the Court must, before overruling a prior decision, be convinced that the decision was wrong and that less injury will result from the overturning decision. McEvoy v Sault Ste Marie, 136 Mich 172; 98 NW 1006 (1904). However, in overturning Woodruff, the majority has not advanced any arguments *733that it was incorrectly decided. If the lead opinion stands, adherence to precedent will be further eroded without a corresponding benefit to the administration of justice.
Finally, neither the parties nor any of the lower courts discussed, argued, or questioned whether MCL 780.131-780.133; MSA 28.969(l)-28.969(3) applied to the defendant. This issue is simply not properly before the Court. MCR 7.302(F)(4)(a).
For these reasons, I would adhere to the decision in People v Woodruff, and hold that it applies to this defendant because the amendments of the 180-day rule were not effective until after her plea to the underlying charges. Because I find that the statute still applies, a determination must also be made regarding whether the defendant’s constitutional and statutory rights were waived by her unconditional guilty plea.
II. WAIVER OF RIGHTS BY UNCONDITIONAL GUILTY PLEA
A majority of the Court of Appeals found that the defendant’s unconditional guilty plea did not waive her rights under the 180-day rule statute, but that she did waive her constitutional speedy trial claims. 183 Mich App 537, 541-542; 455 NW2d 719 (1990). While I agree with the conclusions reached by the majority in the Court of Appeals, I undertake a review of these issues in the hope of helping to clarify its reasoning and resolve a conflict which now exists in that Court. Compare People v Eaton, 184 Mich App 649; 459 NW2d 86 (1990); People v Rivera, 164 Mich App 670; 417 NW2d 569 (1987); People v Williams, 145 Mich App 614; 378 NW2d 769 (1985); People v Parshay, 104 Mich App 411; 304 NW2d 593 (1981), with People v Sickles, 162 Mich App 344; 412 *734NW2d 734 (1987); People v Leroy, 157 Mich App 334; 403 NW2d 555 (1987); People v Farmer, 127 Mich App 472; 339 NW2d 218 (1983); People v Davis, 123 Mich App 553; 332 NW2d 606 (1983).
A. WAIVER BY GUILTY PLEA
In People v New, 427 Mich 482; 398 NW2d 358 (1986), we reviewed which rights, both constitutional and statutory, would be waived by a defendant’s unconditional guilty plea. We set forth a standard that applied the United States Supreme Court’s interpretation of guilty-plea waivers and indicated that "where a defendant’s claim is one that would preclude the state from ever prosecuting the defendant for the crime regardless of his factual guilt, a guilty plea does not waive the defendant’s right to subsequently raise that claim.” New, 427 Mich 488, citing with approval Moody, J., concurring in part and dissenting in part in People v White, 411 Mich 366, 394-399; 308 NW2d 128 (1981). We held that once the defendant unconditionally pleads guilty, the defendant can only appeal those rights and defenses that implicate the very authority of the state to bring the defendant to trial. New, 427 Mich 491 (quoting Moody, J., White, 411 Mich 398). We specifically adopted Justice Moody’s analysis on which rights can be waived by a guilty plea, reiterating that
"[o]nly those rights and defenses which reach beyond the factual determination of defendant’s guilt and implicate the very authority of the state to bring a defendant to trial are preserved. . . . When a defendant pleads guilty, he waives his right to a trial. Therefore, he necessarily gives up all the rights and challenges associated with that *735trial. Thus, important safeguards relating to the capacity of the state to prove defendant’s factual guilt, and those regulating the prosecution’s conduct at trial are among those defendant waives when he pleads guilty. These rights, which essentially relate to the gathering and presentation of evidence, are lost even if a successful challenge would provide a 'complete defense’ by in effect rendering the state unable to continue with the prosecution.” [427 Mich 492-493. Citations omitted, first and second emphasis in original, third emphasis added.]
As this decision indicates, only those rights that prevent the state from initially bringing the defendant to trial are preserved in the face of an unconditional guilty plea. As noted by Justice Levin in People v Reid, 420 Mich 326; 362 NW2d 655 (1984), another way to determine what rights are waived by an unconditional guilty plea is to distinguish between those defenses that are "similar” to jurisdictional defenses that are not waived and rights that are "similar” to nonjurisdictional defenses that are waived. With this background, the Court can determine whether the defendant has waived her constitutional and statutory rights.
B. APPLICATION TO THE CONSTITUTIONAL RIGHT TO SPEEDY TRIAL
Although the defendant has only argued that her right to a speedy trial under the Michigan Constitution is not waived, the result would be the same whether the defendant had alleged rights under either the Michigan Constitution or the federal constitution. The Michigan Constitution, Const 1963, art 1, § 20, states:
*736In every criminal prosecution, the accused shall have the right to a speedy and public trial . . . .[3]
The federal constitution, US Const, Am VI, also states:
In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial ....
We have always interpreted these two constitutional rights in a similar manner. See People v Hill, 402 Mich 272; 262 NW2d 641 (1978); People v Hall, 391 Mich 175, 183-185; 215 NW2d 166 (1974); People v Harrison, 386 Mich 269; 191.NW2d 371 (1971). To determine whether the constitutional right to speedy trial was waived by the defendant’s unconditional guilty plea, we should review whether that right is concerned with the factual guilt of the defendant or the ability of the state to bring charges against the defendant.
We previously determined that one purpose of the constitutional right to speedy trial is to try the accused within a reasonable period of time. People v Den Uyl, 320 Mich 477; 31 NW2d 699 (1948). We determined that the right to speedy trial both facilitates prosecution and prevents undue and prolonged prosecutions that may harm the defendant. People v Collins, 388 Mich 680; 202 NW2d 769 (1972). The right to speedy trial also prevents undue and oppressive incarceration, minimizes the anxiety and concern that normally accompany criminal accusations, and limits the possibility that long delays will impair the ability of the accused to defend himself. United States v Ewell, 383 US 116, 120; 86 S Ct 773; 15 L Ed 2d 627 (1966), overruled on other grounds Chapman v *737California, 386 US 18; 87 S Ct 824; 17 L Ed 2d 705 (1967). The United States Supreme Court has stated that prejudice to the defendant’s ability to defend himself at trial is the most important concern encompassed by the right to speedy trial. Barker v Wingo, 407 US 514, 532; 92 S Ct 2182; 33 L Ed 2d 101 (1972). Factors used to determine prejudice to the defendant’s ability to defend himself include whether witnesses will become unavailable, whether witnesses will have a loss of memory and the credibility of witnesses before the court.
I find that two federal cases help analyze whether the constitutional right to speedy trial is waived by the defendant’s unconditional guilty plea. Although many of the federal circuit courts have found that the constitutional right to speedy trial is waived by a guilty plea, see, e.g., United States v LoFranco, 818 F2d 276 (CA 2, 1987); Tiemens v United States, 724 F2d 928 (CA 11, 1984); United States v Saldana, 505 F2d 628 (CA 5, 1974); Pate v United States, 297 F2d 166 (CA 8, 1962), only one has stated the reasons why such a finding is appropriate. United States v O’Donnell, 539 F2d 1233 (CA 9, 1976).4 The Ninth Circuit indicated that the purpose of the Sixth Amendment is to insure that the factual guilt of the defendant is validly established. The O’Donnell court stated:
The existence of [Sixth Amendment] violations is consistent with guilt as a matter of fact. If guilt can be validly established such violations are not logically inconsistent therewith. While such violations preclude the establishment of guilt by trial, that is the extent of their reach. The establish*738ment of guilt by a proper plea is not condemned by these protections. The Constitution protects the accused from conviction by trial but not a conviction by way of a plea of guilty. [Id. at 1237.]
As this analysis indicates, the constitutional right to speedy trial is concerned with establishing guilt as a matter of fact. Once guilt is established by a proper unconditional guilty plea, the constitutional right is no longer applicable.
I also find the reasoning in United States v MacDonald, 435 US 850; 98 S Ct 1547; 56 L Ed 2d 18 (1978), although concerned with the issue of appealability, especially persuasive in its review of the constitutional right to speedy trial. As the United States Supreme Court noted, the resolution of a speedy trial claim requires a careful assessment of the particular facts of a case. MacDonald, 435 US 858. The Court indicated that most speedy trial claims are best considered "only after the relevant facts have been developed at trial.” Id. The Court continued in this vein of analysis, stating that the events of trial and the question of prejudice to the defense are intertwined. Id. at 859. The Court then made the following statements which clearly indicate that the concern of the constitutional right to speedy trial is determining the factual guilt of the defendant:
Even if the degree of prejudice could be accurately measured before trial, a speedy trial claim nonetheless would not be sufficiently independent of the outcome of the trial to warrant pretrial appellate review. ... [A] central interest served by the Speedy Trial Clause is the protection of the factfínding process at trial. The essence of a defendant’s Sixth Amendment claim in the usual case is that the passage of time has frustrated his ability *739to establish his innocence of the crime charged. Normally, it is only after trial that that claim may fairly be assessed. ... It is the delay before trial, not the trial itself, that offends against the constitutional guarantee of a speedy trial. . . . Furthermore, in most cases, as noted above, it is difficult to make the careful examination of the constituent elements of the speedy trial claim before trial. [Id. at 859-861. Emphasis added.]
I agree with this analysis and would find that the constitutional right to speedy trial, whether under the Michigan or federal constitution, relates to determining the factual guilt of the defendant. The right to speedy trial is concerned with the prejudice to the defendant in defending himself against the charges brought by the state, with the memory of witnesses, and the availability of those witnesses. It is not concerned with the ability of the state to bring the charges against a defendant in court. Therefore, I would hold that the constitutional right to speedy trial is waived by a defendant’s unconditional guilty plea. I would affirm the decision of the Court of Appeals on this issue.
C. APPLICATION TO THE STATUTORY 180-DAY RULE
MCL 780.133; MSA 28.969(3) limits the ability of a court to decide a matter that violates the 180-day rule:
In the event that, within the time limitation set forth in section 1 of this act, action is not commenced on the matter for which request for disposition was made, no court of this state shall any longer have jurisdiction thereof, nor shall the untried warrant, indictment, information or complaint be of any further force or effect, and the *740court shall enter an order dismissing the same with prejudice. [Emphasis added.][5]
One panel of the Court of Appeals, in addition to the dissent in this case, has stated that the reference to jurisdiction in this section refers to personal jurisdiction and that the bar to the court’s jurisdiction is waived by a defendant’s unconditional guilty plea. See People v Eaton, supra.
As noted by the Court of Appeals majority in this case, the question is whether the statute refers to the authority of the state to bring an action in court or to the factual guilt of the defendant. The only issue under the statute relates to the expiration of the pertinent 180-day period, not the ability to determine guilt or innocence, New, supra at 492-493, and no trial is needed to determine whether the 180-day rule has been complied with. As we noted in People v Harrison, supra, if the prosecution does not comply with the statute, the trial court has no jurisdiction over the "matter.” Harrison, 386 Mich 276. Harrison indicates that we previously interpreted this unambiguous statute as removing the subject-matter jurisdiction of the court and the ability of the state to bring a prosecution against a defendant in respect to the 180-day rule. In fact, it is difficult to imagine how the Legislature could have more clearly stated the principle that there can be no trial if the 180-day rule has not been complied with.
The language of the statute indicates that, in addition to divesting the court of all jurisdiction over the defendant, the court must dismiss the charges before it with prejudice. The statute also indicates that the untried warrant, indictment, *741information or complaint has no further force or effect — that it is null and void. The statute, on its face, refers to the ability of the trial court to hear a prosecution brought by the state regardless of the merits. Because no trial court can hear the prosecution’s case, the statute encompasses a right that prevents the state from bringing the defendant to trial and, therefore, is concerned with the authority of the prosecution to bring an action. The traditional personal versus subject-matter jurisdiction distinction is not pertinent here where the Legislature has spoken so clearly and emphatically. Such a disclaimer of authority cannot be restored by a defendant’s waiver. I would find that the language of this statute clearly and unambiguously refers to the jurisdiction of the court to hear the case regardless of its merits and removes the ability of the state to prosecute the defendant.6
I agree with the analysis by the Court of Appeals in People v Parker, 21 Mich App 399; 175 NW2d 879 (1970), which specifically dealt with whether the 180-day rule was waived by the defendant’s unconditional guilty plea. That Court stated:
The clear import of [§ 3] is to deny jurisdiction to the courts where the provisions of § 1 are not met. . . . [T]he Court stated, with regard to the fact that the prosecutor therein had previously consented to the motion: "This Court has never held that jurisdiction of the subject-matter can be *742conferred by consent or waiver. . . . '[JJurisdiction comes solely from the law, in no degree from consent of litigants. So that neither consent nor anything else can authorize a court to act in a cause outside the sphere which the law has ordained for it.’ ” [Id. at 404-405 (citing Nichols v Houghton Circuit Judge, 185 Mich 654; 152 NW 482 [1915]).]
Defendant was incapable of conferring on the trial court the jurisdiction which had been removed by statute. The trial court was without jurisdiction to accept the guilty plea and the untried complaint, upon which the case was based, was void at the time of the plea. The plea was, therefore, without effect and cannot act as an estoppel. By the terms of the statute the only proper action for the trial court was to enter an order dismissing the case with prejudice. [Parker, supra at 405-406. Emphasis added.]
This decision correctly analyzed the statute currently before this Court and correctly found that the 180-day rule is a defense that is similar to a jurisdictional matter.
Even assuming arguendo that the statutory language was unclear or ambiguous, the purpose of the 180-day rule also supports a conclusion that the defendant did not waive her rights by an unconditional guilty plea. In contrast to the constitutional right to speedy trial, the purpose of the statute is not to deter prejudice to the defendant, although that is one of the effects. As noted in Woodruff, supra at 137, the purpose of the statute is to clear away untried accusations against prison inmates. It also is consistent with legislatively prescribed concurrent sentencing. Id. While, as noted by Woodruff, one of the effects is to prevent prejudice incurred by the defendant due to a delayed trial, Hill, supra at 280, the object and *743purpose of the statute extends far beyond that right. Therefore, the object and purpose of the statute also supports a conclusion that, opposite of the constitutional right to a speedy trial, the defendant did not waive this right by an unconditional guilty plea.
I conclude, as did the majority in the Court of Appeals panel in this case, that the constitutional right to speedy trial was waived by the defendant, but that the statutory right is not waived. Therefore, I would also affirm the Court of Appeals decision on this issue.
III. CONCLUSION
Some may argue that it is inconsistent to find that a defendant’s constitutional right to speedy trial is waived while a statute that also protects the right to speedy trial is not waived. However, as I have previously noted, the statutory right protects purposes and objects that are not included in a defendant’s constitutional right to speedy trial. Therefore, such an interpretation is not inconsistent. I would affirm the decision of the majority of the Court of Appeals in this case and find that the defendant’s conviction is reversed and vacated.7
Cavanagh, C.J., concurred with Brickley, J.The majority seems to imply that because Woodruff was a per curiam opinion, it should be easier to overturn. However, a per curiam opinion is as persuasive as an authored opinion and shows that the Court was united in its reasoning. Dowling v Salliotte, 83 Mich 131, 134-135; 47 NW 225 (1890), overruled on other grounds In re Lewis, 85 Mich 340; 48 NW 580 (1891).
The report on the amendments by the Senate Analysis Section, although not controlling on legislative intent, indicates that the Legislature’s two main concerns included the time constraints imposed on prosecutors and judges when attempting to comply with the 180-day rule and miscalculations of the 180-day period that would lead to a dismissal of charges against a prisoner. Senate Analysis Section, SB 344, October 13, 1987.
This constitutional right to speedy trial has also been enacted into statute. MCL 768.1; MSA 28.1024.
Although United States v Gaertner, 583 F2d 308 (CA 7, 1988), also analyzed this issue, that court simply reiterated the reasoning in O’Donnell.
This language was in the statute as it existed at the time of the defendant’s plea and conviction. Unlike §§ 1, 2, this portion of the statute was not changed by the 1988 amendments.
Justice Boyle suggests that MCL 780.133; MSA 28.969(3) may be ambiguous and, by analogy, should be interpreted similarly to federal opinions on the Interstate Agreement on Detainers (iad). MCL 780.601-780.608; MSA 4.147(1)-4.147(8). However, not only does the iad fail to include the important language of MCL 780.133; MSA 28.969(3) that "no court of this state shall any longer have jurisdiction thereof,” but the iad also states that one of its specific purposes is to abate the "difficulties in securing speedy trial of persons already incarcerated in other jurisdictions.” Therefore, not only is the iad dissimilar on its face, but also in its purpose. See infra, p 743.
While the Court of Appeals also discusses when a defendant should be considered in the custody of the Michigan Department of Corrections, that issue was not presented to this Court. During oral arguments, the prosecutor, when asked about this issue, admitted that it had been abandoned on appeal. Therefore, under MCR 7.302(F)(4)(a), I do not discuss that matter.