GUILT PHASE ISSUES
Cross-examination of Coaccused
In her Proposition of Law No. 1, Green argues that the three-judge panel erred in limiting the defense’s cross-examination of Coulter. After direct examination, Green’s counsel cross-examined Coulter about the specifics of *147her pretrial statements to the police. After a cross-examination three times longer than direct, the panel asked if the parties could stipulate that Coulter had made certain prior statements. The parties so stipulated, and the prior statements were then admitted into evidence so the panel could examine them for inconsistencies.
Cross-examination of a witness is a matter of right, but the “extent of cross-examination with respect to an appropriate subject of inquiry is within the sound discretion of the trial court.” Alford v. United States (1931), 282 U.S. 687, 691, 694, 51 S.Ct. 218, 219, 220, 75 L.Ed. 624, 627, 629. The right of cross-examination includes the right to impeach a witness’ credibility.
In this case, Green clearly had the right to impeach Coulter by cross-examining her about prior statements. However, the defense cross-examination on that point had become tedious and repetitive; counsel simply repeatedly asked if Coulter remembered making certain statements. No dispute existed that Coulter had made these prior statements, which were partially inconsistent with each other and with her in-court testimony. In fact, Coulter admitted she had told the police “a lot of different things” and that she had “lied” to them. These admissions rendered pointless any further questioning as to whether she had made the statements.
A trial judge has broad discretion “to preclude repetitive and unduly harassing interrogation[.]” Davis v. Alaska (1974), 415 U.S. 308, 316, 94 S.Ct. 1105, 1110, 39 L.Ed.2d 347, 353. As stated in Delaware v. Van Arsdall (1986), 475 U.S. 673, 679, 106 S.Ct. 1431, 1435, 89 L.Ed.2d 674, 683, “trial judges retain wide latitude * * * to impose reasonable limits on such cross-examination based on concerns about, among other things, harassment, prejudice, confusion of the issues, the witness’ safety, or interrogation that is repetitive or only marginally relevant.”
In this case, the trial panel acted within its discretion in finding the defense questioning tedious and repetitive, and suggesting that counsel stipulate the prior statements. Defense counsel attempted to impeach Coulter by questioning her about her plea bargain, and her refusal to speak to defense counsel. Further, defense counsel did cross-examine her about her prior statements. In fact, all the evidence of the prior inconsistent statements went to the panel for its consideration.
Additionally, the panel’s suggestion of a stipulation did not prejudice Green. With the prior statements admitted, Green’s counsel could freely point out and argue any inconsistencies that did exist. Moreover, Coulter's brief direct testimony did not provide the crucial evidence against Green. Green’s own confession in which she admitted there was a plan to rob and kill Willis, and admitted stabbing him, together with other evidence constituted overwhelm*148ing evidence of guilt even without Coulter’s testimony. Lack of an opportunity to fully cross-examine is harmless error when there is overwhelming, untainted evidence supporting a conviction. Harrington v. California (1969), 395 U.S. 250, 253-254, 89 S.Ct. 1726, 1728-1729, 23 L.Ed.2d 284, 287-288.
Most crucially, the panel’s findings demonstrate the lack of prejudice because the panel rejected Coulter’s version of the events. Coulter tried to minimize her participation in the murder to that of an accessory, mostly an accessory after-the-fact. However, the panel found both Green and Coulter to be principal offenders. Thus, Proposition of Law No. 1 is rejected.
Ineffective Assistance of Counsel
In Proposition of Law No. 2, Green argues that her counsel’s acceptance of the panel’s suggestion of a stipulation covering Coulter’s prior statements amounted to a denial of Green’s right to the effective assistance of counsel. In addition, Green argues that her counsel made a grievous error by allowing the admission of Coulter’s pretrial statements.
Reversal of a conviction or sentence based on the ineffective assistance of counsel requires satisfying the two-prong standard of Strickland v. Washington (1984), 466 U.S. 668, 104 S.Ct. 2052, 80 L.Ed.2d 674. Strickland requires (a) deficient performance — “errors so serious that counsel was not functioning as the ‘counsel’ guaranteed the defendant by the Sixth Amendment”; and (b) prejudice — “errors * * * so serious as to deprive the defendant of a fair trial, a trial whose result is reliable.” Id. at 687, 104 S.Ct. at 2064, 80 L.Ed.2d at 693.
However, defense counsel’s decision to allow the prior statements into evidence instead of further cross-examining Coulter was a reasonable tactical decision. Since the prior statements were admitted into evidence, counsel could freely argue all inconsistencies without a further belabored cross-examination. The tactical decision to agree to the stipulation fell “within the wide range of reasonable professional assistance.” Id. at 689, 104 S.Ct. at 2065, 80 L.Ed.2d at 694. Thus, counsel did not perform deficiently.
Green also failed to satisfy the second Strickland requirement of prejudice. No reasonable probability exists that, but for counsel’s unprofessional errors, the result of the proceeding would have been different. Strickland at 695, 104 S.Ct. at 2069, 80 L.Ed.2d at 699. Coulter’s testimony was not crucial; Green’s conviction rested upon other compelling, convincing evidence of guilt, which included her confession. Also, the panel essentially accepted Green’s version and found Coulter equally responsible for the robbery and murder. Moreover, no evidence exists that the court considered Coulter’s pretrial statements other than to compare inconsistencies. The three-judge panel *149must be presumed not to have improperly used these statements. See State v. White (1968), 15 Ohio St.2d 146, 151, 44 O.O.2d 132, 136, 239 N.E.2d 65, 70, quoted in State v. Post (1987), 32 Ohio St.3d 380, 384, 513 N.E.2d 754, 759. Thus, Proposition of Law No. 2 lacks merit.
SENTENCING PHASE ISSUES
Circumstances of Offense
In Proposition of Law No. 3, Green argues the trial panel’s sentencing decision failed to specify the aggravating circumstance and improperly relied upon the nature and circumstances of the offense as aggravating circumstances. Admittedly, the panel’s opinion inaccurately asserted: “The nature and circumstances of this savage act far outweigh any mitigating factors.”
However, perusal of the entire panel opinion demonstrates that the panel correctly identified the aggravating circumstance to be that the aggravated murder occurred in the course of an aggravated robbery. When a trial court correctly identifies a statutory aggravating circumstance, “this court will infer that the trial court ‘understood the difference between statutory aggravating circumstances and facts describing the nature and circumstances of the offense.’ ” State v. Wiles (1991), 59 Ohio St.3d 71, 90, 571 N.E.2d 97, 120, quoting State v. Sowell (1988), 39 Ohio St.3d 322, 328, 530 N.E.2d 1294, 1302. Moreover, the panel correctly evaluated the nature and circumstances of the offense when it stated, “there was nothing mitigating about the nature and circumstances of the offense. This was a brutal, purposeful, cold and calculated act that culminated in [aggravated murder].”
Thus, the trial panel did not err. In fact, a trial court or three-judge panel “may rely upon and cite the nature and circumstances of the offense as reasons supporting its finding that the aggravating circumstances were sufficient to outweigh the mitigating factors.” State v. Stumpf (1987), 32 Ohio St.3d 95, 512 N.E.2d 598, paragraph one of the syllabus. See, also, State v. Steffen (1987), 31 Ohio St.3d 111, 117, 31 OBR 273, 278, 509 N.E.2d 383, 390. State v. Davis (1988), 38 Ohio St.3d 361, 528 N.E.2d 925, is distinguishable, since the trial panel in that case improperly delineated four circumstances surrounding the offense as specific aggravating circumstances.
Additionally, this court’s independent assessment of the sentence would cure any deficiency in the trial panel’s sentencing decision. See Clemons v. Mississippi (1990), 494 U.S. 738, 110 S.Ct. 1441, 108 L.Ed.2d 725; State v. Landrum (1990), 53 Ohio St.3d 107, 124, 559 N.E.2d 710, 729; State v. Lott (1990), 51 Ohio St.3d 160, 170, 555 N.E.2d 293, 304. Thus, Proposition of Law No. 3 lacks merit.
*150 Disparity of Sentences
In Proposition of Law No. 4, Green argues the court of appeals erred by not finding the disparity of treatment between Coulter and Green to be a mitigating factor. Pursuant to guilty pleas, it is undisputed that Coulter was sentenced to seven to twenty-five years for involuntary manslaughter and to five to twenty-five years for aggravated robbery, the sentences to run consecutively. Green argues that since the trial panel found the sentence disparity to be a mitigating factor, the court of appeals is equally required to find that disparity to be a mitigating factor.
The state responds to Green’s argument by asserting waiver. But waiver is inapplicable here. Green cannot be expected to raise, in advance, an issue about the court of appeals’ sentencing decision before that court issues its decision.
Nonetheléss, Green’s argument that the court of appeals erred lacks merit. R.C. 2929.05(A) contemplates a separate and independent assessment of the sentence. See State v. Maurer (1984), 15 Ohio St.3d 239, 15 OBR 379, 473 N.E.2d 768, paragraph four of the syllabus. Neither the court of appeals nor this court need be bound by a lower court’s opinion as to whether a factor is mitigating. If a higher court were so bound, the review would not be independent. In fact, R.C. 2929.05(A) specifies that:
“The court of appeals and the supreme court * * * shall review and independently weigh all of the facts and other evidence disclosed in the record in the case and consider the offense and the offender to determine whether the aggravating circumstances * * * outweigh the mitigating factors in the case, and whether the sentence of death is appropriate.” (Emphasis added.)
In a comparable situation, this court has recognized that the individual weighing of mitigating factors is a matter within a decision-maker’s discretion. R.C. 2929.04(B) requires the court to consider an offender’s history, background and character, but the court need not give mitigating weight to that factor if it finds it not mitigating. State v. Stumpf supra, at paragraph two of the syllabus. See State v. Steffen, supra, at paragraph two of the syllabus (“ * * * The fact that an item of evidence is admissible under R.C. 2929.04(B)(7) does not automatically mean that it must be given any weight.”).
Moreover, this court’s independent sentence assessment would cure any defect in the court of appeals’ sentencing decision. State v. Lott, supra; State v. Landrum, supra. The question as to what weight, if any, should be given to the sentence disparity will be addressed in the independent sentence assessment. Proposition of Law No. 4 is rejected.
*151 Proportionality Review
In Proposition of Law No. 5, Green argues that her death sentence must be set aside, pursuant to the statutory proportionality review, because of the disparity between her sentence and Coulter’s sentence.
We have held that “[t]he proportionality review required by R.C. 2929.05(A) is satisfied by a review of those cases already decided by the reviewing court in which the death penalty has been imposed.” State v. Steffen, supra, at paragraph one of the syllabus. See State v. Stumpf, supra, 32 Ohio St.3d at 107, 512 N.E.2d at 610.
Additionally, we have ruled that disparity of sentence does not justify reversal of a death sentence when the sentence is neither illegal nor an abuse of discretion. State v. Jamison (1990), 49 Ohio St.3d 182, 191, 552 N.E.2d 180, 188. Proposition of Law No. 5 lacks merit.
Significance of Mitigation
In Proposition of Law No. 6, Green argues that the state failed to prove beyond a reasonable doubt that the aggravating circumstance outweighs the mitigating factors. Green points out that she had a horrible life and that she is mentally and emotionally retarded. She argues: “Willis was killed by a mentally retarded, emotionally disturbed, doped-up child, who was induced to commit the crime by her drug supplier, who received a 7-25 year sentence as payment for her testimony.”
Green cites no legal authority as to why the aggravating circumstance does not outweigh the mitigating factors, so this issue will be examined in the context of the court’s independent sentence review. Proposition of Law No. 6 is rejected.
Constitutionality of Death-Penalty Statute
In Proposition of Law No. 7, Green argues that Ohio’s death-penalty statute is unconstitutional because it fails to provide for adequate appellate review. Specifically, she contends a proper proportionality review should encompass not only cases where the death penalty was sought but also cases where the death penalty was not sought but could have been sought. Although Green raised this issue in the court of appeals, she did not raise the issue at trial. See State v. Awan (1986), 22 Ohio St.3d 120, 22 OBR 199, 489 N.E.2d 277, syllabus. Moreover, the current system of appellate review has been ruled constitutional. State v. Steffen, supra, 31 Ohio St.3d at 122-124, 31 OBR at 283-284, 509 N.E.2d at 394-395; State v. Jenkins (1984), 15 Ohio St.3d 164, 209, 15 OBR 311, 350, 473 N.E.2d 264, 304. This proposition of law is overruled.
*152In Proposition of Law No. 8, Green further challenges the constitutionality of Ohio’s death-penalty statute. However, Green neither argues nor provides authority for her challenges. Green also waived these issues by not raising them before the trial court. State v. Awan, supra. Additionally, this court has consistently upheld the statute’s constitutionality. State v. Buell (1986), 22 Ohio St.3d 124, 136, 22 OBR 203, 213, 489 N.E.2d 795, 806; State v. Jenkins, supra. Summary disposal is appropriate. State v. Poindexter (1988), 36 Ohio St.3d 1, 520 N.E.2d 568, syllabus. Proposition of Law No. 8 lacks merit.
INDEPENDENT SENTENCE ASSESSMENT
Pursuant to our duties imposed by R.C. 2929.05(A), we now independently review the death-penalty sentence for appropriateness and proportionality.
The evidence establishes beyond a reasonable doubt the aggravating circumstance that Green killed Willis during an aggravated robbery and that she was a principal actor in the murder. Because Green and Coulter planned to rob and kill Willis, which is evidenced by the fact that the victim knew Green and Coulter and both perpetrators put socks on their hands to prevent fingerprints at the scene, the trial panel reasonably found prior calculation and design.
The nature and circumstances of the offense provide few mitigating features. Green and Coulter planned and carried out the deliberate and calculated robbery and murder of an elderly, frail, citizen in his own home. Their motive was simply a desire for more money to buy cocaine. Even assuming that Willis pulled a knife when he suspected a robbery, that fact would scarcely be mitigating. A citizen’s choice to defend himself against an unlawful assault does not lessen the moral culpability of the assault. See State v. Clark (1988), 38 Ohio St.3d 252, 263, 527 N.E.2d 844, 856. However, the cut that Green suffered on her hand in that initial struggle with Willis probably explains the frenzy of her ensuing attack.
Green’s “history, character, and background” do provide mitigating features. Green suffered a terrible childhood: her mother tried to kill her when she was three years old, her alcoholic father beat her frequently, and her stepmother neither loved nor nurtured her. Family fights in which her stepmother pulled a knife to defend herself were frequent. Green became the family scapegoat, and at age thirteen or .fourteen, she went into a juvenile facility. At age fifteen, she became pregnant and suffered a miscarriage. Ultimately, she transferred her deep dependency needs from her boyfriend, Turner, and social worker, Ross, to drugs and alcohol. The evidence clearly established she was chemically dependent on marijuana, cocaine, and alcohol *153and had been so dependent for years. With an IQ of 66, she functioned only very marginally. Dr. Schmidtgoessling described Green as intellectually “ten, eleven, twelve; emotionally, much younger than that, more like seven or eight.”
In our review of any statutory mitigating factors, Willis arguably “induced or facilitated” the offense because he illegally bought food stamps and sold liquor. See R.C. 2929.04(B)(1). However, even if true, no significant mitigating weight need be assigned to this factor. The moral culpability of a murder is not lessened because the frail, elderly victim operated on the fringe of the law. Green did not act under “duress, coercion, or strong provocation,” within the meaning of R.C. 2929.04(B)(2). While Green may have been shocked by the cut on her hand, she brought that upon herself with her plan to rob and kill Willis. Since Green was a principal actor in the offense, R.C. 2929.04(B)(6) is inapplicable.
Green’s very limited intelligence, an IQ of 66, would qualify as a mental defect within R.C. 2929.04(B)(3), although she suffered no mental disease. However, evidence is lacking that her mental defect caused Green to lack “substantial capacity to appreciate the criminality” of her conduct or conform that conduct to law. Nonetheless, Green’s limited intelligence would be a mitigating “other factor” under R.C. 2929.04(B)(7). Green’s age of twenty-four only nominally satisfies the mitigating factor of “youth of the offender,” R.C. 2929.04(B)(4), and is entitled to only slight weight.
As to R.C. 2929.04(B)(5), the trial panel found, as a fact, that Green had three prior adjudications as á juvenile and four adult misdemeanor convictions. The court of appeals agreed that Green’s “history of criminal convictions and delinquency adjudications, does not weigh in Green’s favor because she has previously been convicted of several criminal acts, including theft, drug abuse and resisting arrest.” This finding apparently rests upon a presentence investigation not forwarded as a part of the record of trial. Since Green does not claim the absence of a criminal record, as a mitigating factor, the absence of formal documentation of her record can be considered as harmless error. R.C. 2929.04(B)(5) is thus not applicable.
Under R.C. 2929.04(B)(7), as mitigating “other factors,” we consider the different treatment accorded to Coulter, Green’s remorse, the circumstances of her upbringing, her alcoholism and drug addiction, and her limited intelligence.
Coulter was convicted and sentenced for involuntary manslaughter and aggravated robbery. We determine the possible significance of this mitigating factor is diminished because Coulter pled guilty and Green stabbed the victim.
*154In weighing the aggravating circumstance against mitigating factors, we find that the aggravating circumstance does outweigh the mitigating factors beyond a reasonable doubt. Collectively, Green’s lack of intelligence, family upbringing, and alcohol and drug addiction are entitled to modest weight. In contrast, Green planned and carried out a calculated robbery and murder of a frail, elderly man in his own home. The number and manner of the stab wounds convincingly demonstrate an intention to commit murder. The manner of death and the prior calculation and design tend to negate Green’s later claims of remorse.
The death penalty in this case is neither excessive nor disproportionate, but is appropriate, when compared with other felony-murder cases. See State v. Smith (1991), 61 Ohio St.3d 284, 574 N.E.2d 510; State v. Wiles, supra; State v. Jackson (1991), 57 Ohio St.3d 29, 565 N.E.2d 549; State v. Landrum, supra; State v. Lott, supra; State v. Johnson (1989), 46 Ohio St.3d 96, 545 N.E.2d 636; State v. Van Hook (1988), 39 Ohio St.3d 256, 530 N.E.2d 883; State v. Greer (1988), 39 Ohio St.3d 236, 530 N.E.2d 382; State v. Holloway (1988), 38 Ohio St.3d 239, 527 N.E.2d 831.
Accordingly, the judgment of the court of appeals is affirmed.
Judgment affirmed.
Moyer, C.J., A.W. Sweeney, Douglas and Resnick, JJ., concur. Wright, J., concurs separately. Pfeifer, J., dissents.