PATIENCE DRAKE ROGGENSACK, J.
¶ 1. We review a decision of the court of appeals1 that affirmed the circuit court's2 ruling that admitted an expert [661]*661witness's testimony that established the blood alcohol concentration (BAC) of Michael R. Griep while he was operating his vehicle. The expert witness, Patrick Harding, based his opinion in part on forensic tests conducted by an analyst at the Wisconsin State Laboratory of Hygiene (Wisconsin State Laboratory) who was unavailable for trial. Based on Harding's testimony, Griep was convicted of operating a motor vehicle while intoxicated (third offense).
¶ 2. Griep appealed, contending that his right of confrontation was violated when the circuit court allowed Harding to rely in part on the analyst's forensic test results. The court of appeals affirmed, concluding that Griep's right of confrontation was not violated because Harding reviewed the analyst's forensic test results and other records and formed an independent opinion of Griep's BAC, as approved in State v. Williams,3 2002 WI 58, 253 Wis. 2d 99, 644 N.W.2d 919 and State v. Barton, 2006 WI App 18, 289 Wis. 2d 206, 709 N.W.2d 93. State v. Griep, 2014 WI App 25, ¶¶ 19, 22, 353 Wis. 2d 252, 845 N.W.2d 24.
¶ 3. We conclude that Harding's review of Griep's laboratory file, including the forensic test results of an analyst who was unavailable for trial, to form an independent opinion to which he testified did not violate Griep's right of confrontation. Williams, 253 Wis. 2d 99, ¶ 26; Barton, 289 Wis. 2d 206, ¶ 20. Accordingly, we affirm the court of appeals decision that affirmed the circuit court's admission of Harding's testimony.
[662]*662I. BACKGROUND
¶ 4. This review involves Griep's claimed violation of his right of confrontation regarding Harding's expert testimony that was based in part on results of forensic tests conducted by an analyst who was unavailable for trial. The historic facts are not in dispute.
¶ 5. On Saturday, August 25, 2007, at approximately 12:48 a.m., a Winneconne Police Department officer stopped Griep for speeding, for which he planned to issue a warning ticket. However, while talking with Griep, the officer smelled the odor of alcohol and observed Griep's bloodshot and glassy eyes.
¶ 6. In response to the officer's question about alcohol consumption, Griep stated that he drank a couple of beers at a local bar. When the officer asked Griep to perform field sobriety tests, Griep agreed. Griep's performance on the field sobriety tests indicated that he was intoxicated. After further discussion, Griep admitted he had four beers. Griep agreed to perform a preliminary breath test that also indicated intoxication. The officer reviewed Griep's record, which showed two prior convictions for OWI. The officer transported Griep to a nearby hospital for a blood draw. At the officer's request, hospital staff conducted the blood draw without Griep's consent.4
[663]*663¶ 7. The officer observed a phlebotomist draw Griep's blood and place it in closed vials. The blood kit was properly sealed. The blood kit was secured at the Winneconne Police Department before it was mailed to the Wisconsin State Laboratory.
¶ 8. Wisconsin State Laboratory analyst Diane Kalscheur received and analyzed Griep's blood sample. Kalscheur authored a concise report stating: (1) she received Griep's labeled and sealed blood sample, and (2) Griep's blood was tested for ethanol and that testing revealed a certain ethanol concentration. Thomas Ecker, an Advanced Chemist at the laboratory, conducted a peer review of Kalscheur's report and signed the laboratory report under the statement "As designee of the Director, I do hereby certify this document to be a true and correct report of the findings of the Wisconsin State Laboratory of Hygiene."
¶ 9. At Griep's trial for third-offense OWI, the phlebotomist testified about instructions for collecting blood, using the kit provided by a police officer, and her role in inspecting the blood kit before its use.
¶ 10. Kalscheur was unavailable at the time of trial.5 Instead, the State called Patrick Harding, section chief of the toxicology section of the Wisconsin State Laboratory, as an expert witness. Harding testified that he had reviewed Kalscheur's work and examined the data produced by Kalscheur's testing, specifically the chromatograms, as well as other records associated with the tests Kalscheur performed. Harding said that he was familiar with the process of obtaining blood samples for ethanol testing, shipping them to the laboratory, processing them for analysis, and the analysis of the samples.
[664]*664¶ 11. When the State asked Harding's opinion on whether Kalscheur tested Griep's blood sample consistently with laboratory procedures, defense counsel objected on Confrontation Clause grounds. Harding testified that all indications were that Kalscheur followed the laboratory procedures and that the instrument was working properly. Harding said that the machine's proper function was evident from the results of calibration checks run throughout the course of the tests of Griep's samples. Harding concluded that the results of those calibration checks, in particular those Kalscheur ran immediately before and after the Griep samples, showed the reliability of the machine's results. Harding opined that correctly running the sample through the calibrated instrument resulted in a reliable blood alcohol reading. Harding concluded that after reviewing all of the available data, he came to an independent opinion that the alcohol concentration in Griep's blood was 0.152 grams of ethanol per 100 milliliters of blood. Harding also testified as to laboratory procedures and that if there had been irregularities with the sample, they would have been noted on a form by the analyst. None were noted.
¶ 12. During cross-examination, Harding acknowledged that an analyst could commit misdeeds, possibly without detection. Harding also acknowledged that it is important that the analyst be competent and honest. Harding testified that when he testifies about forensic tests that he has personally completed, he relies on the paperwork and notes he completed at the time of testing because analysts at the laboratory conduct so many tests that no one can remember details about each particular sample without reviewing the notes that were made contemporaneously with the tests.
[665]*665¶ 13. Griep's motion in limine and objection at trial that sought to preclude Harding's testimony were grounded in the Confrontation Clause. He relied on Melendez-Diaz v. Massachusetts, 557 U.S. 305 (2009); Crawford v. Washington, 541 U.S. 36 (2004); and their relationship to Williams and Barton. The circuit court considered the Confrontation Clause issue after conclusion of the presentation of evidence at the bench trial. The circuit court denied Griep's motion; heard closing arguments; adjudged Griep guilty; convicted and sentenced him.
¶ 14. Griep appealed. Before the court of appeals issued its decision, the United States Supreme Court accepted a petition in State v. Bullcoming, 226 P.3d 1 (N.M. 2010). See Bullcoming v. New Mexico, 561 U.S. 1058 (2010) (granting certiorari). The court of appeals held Griep's case in abeyance pending the outcome in Bullcoming because the question presented in that case6 was similar to the question in Griep's appeal.
¶ 15. As the court of appeals was again about to undertake Griep's appeal, the court learned that the United States Supreme Court had granted certiorari in another relevant case, People v. Williams, 939 N.E.2d 268 (Ill. 2010). See Williams v. Illinois, _ U.S. _, 131 S. Ct. 3090 (2011) (granting certiorari). The court of appeals once again held Griep's case to await the outcome in Williams v. Illinois because the decision on the [666]*666question presented7 may have had an effect on Griep's appeal.
¶ 16. On May 15, 2013, the court of appeals certified the appeal to us.8 On June 14, 2013, we held the certification in abeyance pending our disposition of State v. Deadwiller. See State v. Deadwiller, 350 Wis. 2d 138, 834 N.W.2d 362 (decided July 16, 2013). On November 20, 2013, we refused certification. The court of appeals issued its opinion February 19, 2014, and held that Barton remained good law. Griep, 353 Wis. 2d 252, ¶ 22. The court held that "the availability of a well qualified expert, testifying as to his independent conclusion about the ethanol testing of Griep's blood as evidenced by a report from another state lab analyst, was sufficient to protect Griep's right to confrontation." Id.
II. DISCUSSION
A. Standard of Review
¶ 17. We review whether Harding's testimony, particularly his reliance on testing conducted by [667]*667Kalscheur, violated Griep's right of confrontation.189 While "a circuit court's decision to admit evidence is ordinarily a matter for the court's discretion, whether the admission of evidence violates a defendant's right of confrontation is a question of law subject to independent appellate review." Deadwiller, 350 Wis. 2d 138, ¶ 17 (quoting Williams, 253 Wis. 2d 99, ¶ 7).
B. Confrontation Clause
¶ 18. Griep argues that Harding's testimony violated his rights under the Confrontation Clause. The Sixth Amendment Confrontation Clause provides "In all criminal prosecutions, the accused shall enjoy the right... to be confronted with the witnesses against him." We begin by recognizing that the Sixth Amendment right of an accused to confront the witnesses against him is a fundamental right, as made applicable to and obligatory on the states by the Fourteenth Amendment. Pointer v. Texas, 380 U.S. 400, 403 (1965) (concluding that the Sixth Amendment right to confront witnesses against the accused is a fundamental right).
f 19. In Williams, we first examined whether a laboratory unit leader's trial testimony, based in part on a report authored and tests conducted by an analyst who did not testify at trial, violated the Confrontation Clause. Williams was on trial for possession of cocaine with intent to deliver. Williams, 253 Wis. 2d 99,
[668]*668¶¶ 3-4. A crime laboratory unit leader testified as to her expert opinion based in part on a state crime laboratory report that showed a substance in Williams' possession was cocaine base. Williams argued his right of confrontation was violated when the crime laboratory unit leader testified rather than requiring the analyst who performed the laboratory tests to testify and also when the circuit court admitted the state crime laboratory report. Id., ¶ 4.
¶ 20. We held that the unit leader's testimony did not violate Williams' right of confrontation. Id., ¶¶ 20, 26. We stated:
[T]he presence and availability for cross-examination of a highly qualified witness, who is familiar with the procedures at hand, supervises or reviews the work of the testing analyst, and renders her own expert opinion is sufficient to protect a defendant's right to confrontation, despite the fact that the expert was not the person who performed the mechanics of the original tests.
Id., ¶ 20. Regarding the independent expert's opinion, we opined that "an expert who forms an opinion based in part on the work of others and an expert who merely summarizes the work of others" are quite different because in that later instance, the expert would be "a mere conduit for the opinion of another." Id., ¶ 19.
¶ 21. We concluded that the expert witness in Williams was highly qualified to render an expert opinion and was closely connected to the tests and procedures involved in the actual tests. Id., ¶¶ 21-22. The expert witness was a unit leader at the Wisconsin State Laboratory with nine years of experience, a bachelor's degree in chemistry with some graduate courses, who had substantial experience analyzing for the presence of controlled substances. Id., ¶ 21. The [669]*669witness also was familiar with the various tests and had performed peer review on the tests. Id., ¶ 22. The expert's peer review involved comparing the notes with the evidence and the conclusions, and conducting an overall examination of the data "making sure that all the notes coincide with the evidence, [and] that the data coincides with [the] conclusion." Id. Additionally, we determined that the witness was "not merely a conduit" for another's opinion, but rather, she testified as to her independent opinion based in part on facts and data gathered by someone else.9 Id., ¶ 25.
¶ 22. We also considered whether a laboratory report authored by the non-testifying analyst violated the defendant's right of confrontation when it was admitted into evidence. Id., ¶ 32. We analyzed the admissibility of the report and the expert witness's testimony as two separate issues. Id. First, we held that the laboratory report was not properly admitted as a business record under Wis. Stat. § 908.03(6) (1997-98), in part because it was prepared for litigation. Id., ¶ 49. However, we concluded that the report's admission was harmless error. Id., ¶ 50. Second, we evaluated the expert witness's testimony. In reaching our conclusion that admission of the report was harmless error, we regarded the expert witness's testimony as compelling and credible evidence from which the [670]*670jury could have concluded the substance at issue was cocaine. Id,., ¶ 52. Stated otherwise, the witness's opinion was constitutional, and that conclusion was unrelated to whether the admission of the report violated the Confrontation Clause.
¶ 23. Griep's contention appears to be addressed by the rule we set out in Williams. However, before proceeding to apply Williams to his claimed Confrontation Clause violation, we consider whether federal opinions issued subsequent to Williams, including Crawford, Bullcoming v. New Mexico, _ U.S. _, 131 S. Ct. 2705 (2011), and Williams v. Illinois, _ U.S. _, 132 S. Ct. 2221 (2012), affect our conclusions in Williams.
1. Relevant federal opinions
¶ 24. In 2004, the United States Supreme Court took up the Confrontation Clause in Crawford. At Crawford's trial for assault and attempted murder, he claimed self-defense. Crawford, 541 U.S. at 40. The defendant's wife did not testify "because of the state marital privilege, which generally [barred] a spouse from testifying without the other spouse's consent." Id. "[The] privilege [did] not extend to a spouse's out-of-court statements admissible under a hearsay exception." Id. The state sought to admit the wife's statement to police as a statement against penal interest. Id. On review, the Supreme Court held that admission of out-of-court testimonial statements violated the Confrontation Clause unless the declarant is unavailable and the defendant had a prior opportunity to cross-examine the declarant. Id. at 59.
¶ 25. Crawford's discussion of testimonial statements of an unavailable declarant is consistent with the Williams requirement that in order to be permitted [671]*671to testify an expert must form an independent opinion when the expert's opinion is based in part on tests performed by another analyst.10 See Williams, 253 Wis. 2d 99, ¶¶ 19, 25. This Williams' requirement prevents a Crawford violation of the Confrontation Clause because out-of-court statements are not admitted as evidence, but rather, they are replaced by independent opinions based both on data collected by others and on the expert's own analysis.
¶ 26. Subsequent to the Supreme Court's decision in Crawford, the court of appeals applied Williams. Barton, 289 Wis. 2d 206, ¶¶ 9, 20. In Barton, the court of appeals' discussion focused on whether a unit leader at the state crime laboratory could testify based in part on tests performed by another analyst. The unit leader at the state crime laboratory testified about chemical tests performed by an analyst who was unavailable at trial. Id., ¶ 4. The expert witness conducted peer review of the analyst's tests and testified as to his independent expert opinion. Id., ¶¶ 4,16. The State did not seek to admit the laboratory report that detailed the analyst's test results. Id., ¶ 4.
¶ 27. The court of appeals applied Williams and held the testimony did not violate Barton's right of confrontation.11 Id., ¶¶ 9-13, 16, 20. The court con-[672]*672eluded that the expert witness was a highly qualified expert who presented his independent opinion. Id., ¶ 13. The court noted that the witness held a supervisory position, had an academic background in the area, and had significant experience with the crime laboratory, all of which were similar to the expert in Williams. Id. The witness testified that he had reviewed the case file, including the gas chromatography tests, as a formal peer review. He explained the uniform procedures employed by the crime laboratory for the tests at issue. He said that based in part on his review of the case file, the analyst had followed the required procedures in the tests. Id., ¶ 14. The court concluded that the expert's testimony was an independent opinion based on his own experience and his own analysis of the testing. Id., ¶¶ 14-16. The court of appeals held that under Williams, the witness's testimony did not violate Barton's right of confrontation and was admissible. Id., ¶ 16.
¶ 28. The court of appeals also clarified the effect of Crawford on Williams: "The holding in Crawford does not undermine our supreme court's decision in Williams. Williams is clear: A defendant's confrontation right is satisfied if a qualified expert testifies as to his or her independent opinion, even if the opinion is based in part on the work of another." Id., ¶ 20.
¶ 29. In Melendez-Diaz, the United States Supreme Court again took up the admissibility of forensic reports created by a non-testifying laboratory analyst. At issue was whether affidavits reporting forensic analyses were testimonial, "rendering the affiants 'wit[673]*673nesses' subject to the defendant's right of confrontation under the Sixth Amendment." Melendez-Diaz, 557 U.S. at 307. Those affidavits showed a substance connected to the defendant was cocaine, and were created specifically to serve as evidence at a criminal trial. Id. at 324. The Supreme Court held that the forensic laboratory reports were testimonial statements subject to the Confrontation Clause, and therefore, defendants have a right to confront the authoring analyst at trial. Id. at 311. The Court recognized that Melendez-Diaz falls within the Crawford line of cases: "This case involves little more than the application of our holding in Crawford v. Washington .... The Sixth Amendment does not permit the prosecution to prove its case via ex parte out-of-court affidavits." Id. at 329. Melendez-Diaz's holding regarding the testimonial nature of laboratory reports does not alter our conclusion in Williams that a defendant's right to confront witnesses against him is not violated when a testifying expert reviews the case file and comes to an independent conclusion, even though the expert's opinion is based in part on tests performed by another analyst.12 See Williams, 253 Wis. 2d 99, ¶¶ 19, 25.
[674]*674¶ 30. In its 2011 decision in Bullcoming, the United States Supreme Court next revisited the Confrontation Clause's applicability to forensic laboratory reports. At Bullcoming's trial on charges of driving while intoxicated, the trial court admitted a forensic laboratory report certifying that Bullcoming's BAC was above the BAC threshold for driving under the influence. Bullcoming, 131 S. Ct. at 2709. The analyst who certified the laboratory report did not testify. Instead, the prosecution called a different analyst as a witness. Id. The witness was familiar with the laboratory's testing procedures, but did not participate in, observe, or review the testing of the defendant's blood sample. Id. at 2709, 2712. The Court focused on whether the prosecution could admit a laboratory report containing a testimonial certification through the in-court testimony of a witness that did not certify the report or perform or observe the test that was the subject of the report. Id. at 2710. The Court held that admission of the report violated the defendant's right of confrontation and reiterated the rule in Crawford. Id. at 2713.
Our answer is in line with controlling precedent: As a rule, if an out-of-court statement is testimonial in nature, it may not be introduced against the accused at trial unless the witness who made the statement is unavailable and the accused has had a prior opportunity to confront that witness.
Id.
¶ 31. The Supreme Court's discussion in Bull-coming differs from the section of our Williams decision that is relevant to Griep's contention of a Confrontation Clause violation. In Bullcoming, the prosecution admitted the forensic report as a business record in [675]*675violation of the Confrontation Clause. Id. at 2712. Williams also concludes that the forensic report cannot properly be admitted as a business record. Williams, 253 Wis. 2d 99, ¶ 49. However, in Williams, the expert witness reviewed the work of the testing analyst, was familiar with the procedures at hand, and rendered an independent opinion. Id., ¶¶ 21-22. The testimony in Bullcoming is not the independent opinion of an expert. See Bullcoming, 131 S. Ct. at 2712, 2716 (stating that the witness did not review the test results and prosecution never asserted that the witness had an independent opinion concerning the defendant's BAC). Therefore, when an expert witness reviews data yielded by laboratory tests and reaches his or her own independent opinion based on that data and his or her own knowledge, Williams applies and Bullcoming provides no guidance.
¶ 32. Justice Sotomayor emphasized the limited reach of Bullcoming in her concurrence. Id. at 2722 (Sotomayor, J., concurring). She wrote separately to highlight her view that the laboratory report was testimonial because its primary purpose was evidentiary, but she also wrote "to emphasize the limited reach of the Court's opinion." Id. at 2719. Justice Sotomayor distinguished Bullcoming from other cases where the trial witness "is a supervisor, reviewer, or someone else with a personal, albeit limited, connection to the scientific test at issue." Id. at 2722. She also distinguished cases where the expert witness was asked for and gave an independent opinion about underlying testimonial reports that were not admitted into evidence. Id. She noted that in Bullcoming, the prosecution acknowledged that the witness offered no opinion about the BAC. Justice Sotomayor concluded: "We would face a different question if asked [676]*676to determine the constitutionality of allowing an expert witness to discuss others' testimonial statements if the testimonial statements were not themselves admitted as evidence." Id. Justice Sotomayor's concurrence reinforces our conclusion that Bullcoming does not guide our decision when the issue is the independent opinion of an expert witness who has reviewed the forensic test results, rather than the admissibility of an underlying forensic report.
¶ 33. The Supreme Court provided guidance on when out-of-court testimonial statements are admissible, when statements are testimonial, and under what circumstances testimonial laboratory reports are admissible in Crawford, Melendez-Diaz, and Bullcoming. Crawford, 541 U.S. at 59; Melendez-Diaz, 557 U.S. at 311; Bullcoming, 131 S. Ct. at 2713. Wisconsin cases, Williams and Barton, go a step further and address situations where the State does not offer the laboratory report into evidence, but instead offers the independent opinion of an analyst who did not perform the tests. Williams, 253 Wis. 2d 99, ¶ 20; Barton, 289 Wis. 2d 206, ¶ 16. Stated otherwise, federal Confrontation Clause opinions predating Williams v. Illinois do not affect our rule in Williams, or the court of appeals' application in Barton. We now examine whether Williams v. Illinois affects Williams and Barton.
¶ 34. Williams v. Illinois, the Supreme Court's most recent Confrontation Clause opinion that examines presentation of expert opinion, involved Williams' bench trial for rape. There, the prosecutor called a forensic specialist at the Illinois State Police laboratory who testified that according to the police laboratory's business records, the victim's vaginal swabs were sent to Cellmark, an outside, accredited laboratory. Williams v. Illinois, 132 S. Ct. at 2229. Cellmark [677]*677returned the swabs to the police laboratory, and set out a male DNA profile derived from the semen on the swabs. Id. Upon receipt of the report and profile, a police laboratory analyst conducted a search of the Illinois State DNA database, revealing that Williams' DNA matched the DNA profile obtained from the swabs processed by Cellmark. Id. The police laboratory analyst testified about standard procedures, about Cellmark's accreditation, and that her comparison of the DNA profiles on the Illinois database with the Cellmark profile resulted in a match. Id. at 2229-30. The Cellmark DNA profile was not admitted into evidence. Id. at 2230. The defendant objected to the expert's testimony on Confrontation Clause grounds. Id. at 2231. The trial court ruled against Williams. Id.
| 35. Williams v. Illinois is a plurality opinion with Justice Thomas concurring in judgment.13 Id. at 2227. Aplurality of the Supreme Court held the expert's testimony did not violate Williams' right of confrontation. However, the Court's four-one-four division "left no clear guidance about how exactly an expert must phrase [his] testimony [that concerns] the results of testing performed by another analyst in order for the [expert's] testimony to be admissible." United States v. Maxwell, 724 F.3d 724, 727 (7th Cir. 2013); see also Williams v. Illinois, 132 S. Ct. at 2277 (Kagan, J., dissenting); id. at 2255 (Thomas, J., concurring in the result, but with no portion of the plurality's reasoning).
| 36. In determining what effect a plurality opinion has on our review, we apply Marks v. United States, [678]*678430 U.S. 188, 193 (1977). Deadwiller, 350 Wis. 2d 138, ¶ 30; see also Vincent v. Voight, 2000 WI 93, ¶ 46 n.18, 236 Wis. 2d 588, 614 N.W.2d 388; Lounge Mgmt., Ltd. v. Town of Trenton, 219 Wis. 2d 13, 21-22, 580 N.W.2d 156 (1998). "When a fragmented [Supreme] Court decides a case and no single rationale explaining the result enjoys the assent of five Justices, the holding of the Court may be viewed as that position taken by those Members who concurred in the judgments on the narrowest grounds." Marks, 430 U.S. at 193 (internal quotations and citations omitted). The Marks narrowest grounds rule is applicable only when one opinion is narrower than the other or is a logical subset of another, broader opinion. Deadwiller, 350 Wis. 2d 138, ¶ 30 (citing Evan H. Caminker, Precedent and Prediction: The Forward-Looking Aspects of Inferior Court Decisionmaking, 73 Tex. L. Rev. 1, 33 n.120 (1994)); King v. Palmer, 950 F.2d 771, 781 (D.C. Cir. 1991). If no "theoretical overlap" exists between the rationales of the plurality and the concurrence, it is binding only as to its "specific result." Deadwiller, 350 Wis. 2d 138, ¶ 30 (citing Berwind Corp. v. Comm'r of Soc. Sec., 307 F.3d 222, 234 (3d Cir. 2002)).14 A plurality opinion [679]*679without overlapping rationales requires a specific result only when the parties are in a "substantially identical position." Id.
¶ 37. Williams v. Illinois does not contain a "narrowest opinion." Williams v. Illinois, 132 S. Ct. at 2228, 2244-45 (Breyer, J., concurring), 2255 (Thomas, J., concurring); Deadwiller, 350 Wis. 2d 138, ¶ 32. Five justices of the United States Supreme Court concluded in Williams v. Illinois that, in certain circumstances, the Confrontation Clause does not bar an expert witness from basing his or her testimony on a forensic laboratory report prepared by another analyst when the defendant was never given an opportunity to cross-examine the analyst who prepared the report or conducted the forensic testing. Williams v. Illinois, 132 S. Ct. at 2228. However, no opinion gathered a majority of the Court. Id. at 2244, 2252 (Breyer, J., concurring), 2261 (Thomas, J., concurring). The four justices of the plurality concluded that the testimony did not violate the Confrontation Clause because the report was not used to prove the truth of the matter asserted and its primary purpose was not to accuse a targeted individual of a crime. Id. at 2243. While a fifth justice agreed with the disposition of the case, he concluded that the report was non-testimonial because it "lacked the requisite 'formality and solemnity' to be considered 'testimonial.' "15 Id. at 2255 (Thomas, J., concurring). [680]*680Four justices rejected both the plurality's primary purpose test and Justice Thomas' solemnity-based test and instead concluded that the expert testimony was "functionally identical to the 'surrogate testimony'" in Bullcoming and that Bullcoming controlled the outcome.16 Id. at 2267 (Kagan, J., dissenting). As no opinion overlaps with another, the Marks narrowest grounds rule does not apply to Williams v. Illinois. Marks, 430 U.S. at 193; Deadwiller, 350 Wis. 2d 138, ¶ 30; King, 950 F.2d at 781.
¶ 38. Therefore, Williams v. Illinois is binding only as to its "specific result." Deadwiller, 350 Wis. 2d 138, ¶ 30 (citing Berwind Corp., 307 F.3d at 234). A plurality opinion without a narrowest grounds concurrence requires a specific result when the parties are in a substantially identical position. Berwind, 307 F.3d at 234. Griep is not in a substantially identical position to the parties in Williams v. Illinois. The difference between Griep's circumstances and those in Williams v. Illinois is illustrated by our recent opinion in Deadwiller.
¶ 39. Deadwiller is our sole Confrontation Clause case since Williams v. Illinois. In Deadwiller, the defendant was identified as a suspect in a sexual assault through a DNA profile derived at an out-of-[681]*681state laboratory from the victim's vaginal and cervical swabs, which matched Deadwiller's profile in Wisconsin's DNA database. Deadwiller, 350 Wis. 2d 138, ¶ 5. We considered application of the Marks narrowest ground principle to Williams v. Illinois, but concluded that no Williams v. Illinois concurring opinion fit the narrowest grounds rule. Id., ¶¶ 30-32. We recognized that Williams v. Illinois would still be binding as to its specific result when the parties are in a substantially identical position. Id., ¶ 30 (citing Berwind, 307 F.3d at 234). We compared the facts of each case and concluded that Deadwiller and Williams were in substantially identical positions, and therefore we were bound by the specific result in Williams v. Illinois. Id., ¶ 32. In concluding we were so bound, we noted similarities in the cases. Id.
In both cases, the victim reported the crime and underwent a sexual assault examination, which produced vaginal swabs containing DNA of the perpetrator. In both cases, police officers picked up the evidence, inventoried the evidence, and sent the evidence to the state crime lab, which then sent the evidence to an out-of-state laboratory for DNA testing. Further, the out-of-state laboratory in both cases sent back the genetic material and a DNA profile of the perpetrator produced from the vaginal swabs. In both cases, state crime lab analysts entered the DNA profile into a DNA database, which resulted in a match to the defendant. When called to testify, the state crime lab analyst in both cases reported that the DNA profile sent by the out-of-state lab matched the DNA profile resulting from the database. The DNA profile was not introduced into evidence in either case. Prosecutors in both cases introduced inventory reports, evidence receipts, and testimony to prove a chain of custody, i.e. that the DNA profile was produced from swabs taken from the victims.
[682]*682¶ 40. Deadwiller concludes the lines of relevant state and federal Confrontation Clause cases. In review, Williams and Barton establish that an expert witness does not violate the Confrontation Clause when his or her opinion is based in part on data created by a non-testifying analyst if the witness "was not merely a conduit." Williams, 253 Wis. 2d 99, ¶¶ 20, 25; accord Barton, 289 Wis. 2d 206, ¶¶ 13-14. In other words, if the expert witness reviewed data created by the non-testifying analyst and formed an independent opinion, the expert's testimony does not violate the Confrontation Clause. Williams, 253 Wis. 2d 99, ¶ 20; Barton, 289 Wis. 2d 206, ¶¶ 13-14. No federal decision addresses this type of expert testimony. In Crawford, admission of testimonial statements of an unavailable declarant violated the Confrontation Clause if the declarant was unavailable and the defendant had no prior opportunity to cross-examine. Crawford, 541 U.S. at 59. Melendez-Diaz applied Crawford to conclude that testimonial statements made in a forensic report that was admitted into evidence, but was created by a non-testifying analyst, violated the Confrontation Clause. Melendez-Diaz, 557 U.S. at 311. The facts of Bullcoming go one step further, involving both the admission of a testimonial forensic report and testimony of an expert witness who did not conduct the tests or offer an independent opinion. Bullcoming, 131 S. Ct. at 2712, 2716. However, Crawford, Melendez-Diaz, and Bullcoming do not address a situation where a non-testifying analyst's testimonial statements do not come into evidence, i.e., where the testimonial forensic report is not admitted and the expert witness who testifies at trial gives his or her independent opinion after review of laboratory [683]*683data created another analyst. Stated otherwise, when a non-testifying analyst documents the original tests "with sufficient detail for another expert to understand, interpret, and evaluate the results," that expert's testimony does not violate the Confrontation Clause. David H. Kaye, David E. Bernstein, & Jennifer L. Mnookin, The New Wigmore: Expert Evidence, § 4.10.2, pp. 204-05 (2d ed. 2010); accord Williams, 253 Wis. 2d 99, ¶ 20; Barton, 289 Wis. 2d 206, ¶¶ 13-14. Williams v. Illinois has not altered Confrontation Clause jurisprudence, which we confirmed in Deadwiller. See Deadwiller, 350 Wis. 2d 138, ¶ 30.
2. Griep's circumstances
¶ 41. In the case now before us, we compare the parties' positions in Griep to that of the parties' positions in Williams v. Illinois and conclude that they are not in substantially identical positions. First, this is not a sexual assault case. Cf. Williams v. Illinois, 132 S. Ct. at 2229. Here, analysts used a laboratory test, gas chromatography, to determine Griep's BAC, which differs from the creation of a DNA profile and the process of matching DNA profiles that was used in Williams v. Illinois. Cf. id. Second, the analyst conducted all of the laboratory work here in the same laboratory that employed the expert witness, rather than utilizing work provided by an outside laboratory. Cf id. at 2229-30. The only similarity between this case and Williams v. Illinois is that the prosecution did not introduce the forensic reports into evidence in either case. Id. at 2230.
¶ 42. We conclude Griep is not in a substantially identical position to Williams. Therefore, the specific result of Williams v. Illinois is not binding in this case as it was in Deadwiller. Cf. Deadwiller, 350 Wis. 2d [684]*684138, ¶ 32. For that reason, we need not further discuss the various rationales of Williams v. Illinois as we did in Deadwiller. See id., ¶¶ 33-36.
¶ 43. Aside from its discussion of the Williams v. Illinois rationales, Deadwiller also provides our only post -Williams v. Illinois analysis of Williams and Barton. Id., ¶¶ 37-40. We concluded that Williams and Barton are consistent with our application of the specific result of Williams v. Illinois. Id., ¶ 37. We applied Williams and Barton to the facts in Deadwiller and determined that the expert witness reviewed the out-of-state laboratory's procedures and offered his independent conclusion, and therefore did not violate the defendant's right of confrontation. Id., ¶ 40.
¶ 44. As we tacitly recognized in Deadwiller, nothing in Williams u. Illinois affects our decision in Williams and its application by the court of appeals in Barton17 See id., ¶¶ 37-40. In addition, Williams v. Illinois is not otherwise useful to our analysis here because Marks does not apply18 and Griep is not in a substantially identical position to the convicted perpetrator.19 As Williams v. Illinois does not affect our [685]*685conclusion in Williams or the court of appeals' application in Barton, our remaining task is to apply Williams and Barton to this case.
C. Admission of Patrick Harding's Testimony
¶ 45. We rely on pr e-Williams v. Illinois opinions, as well as our only Confrontation Clause decision after Williams v. Illinois, Deadwiller, to determine whether the State's witness, Patrick Harding, testified in violation of Griep's right of confrontation.20 Harding served as the State's expert witness for Griep's BAC and testified in place of Kalscheur, who was not available at the time of trial. While Harding was not an official peer reviewer of Kalscheur's forensic tests, Harding testified that he examined the data "available the day after the analysis for the person that reviewed the report when it went out." His review included chromatograms and results of the entire analytical run that Kalscheur conducted, which described the calibration checks that were used to assess whether the machine was performing properly and whether the test was run correctly.21
[686]*686¶ 46. Harding testified that all indications were that Kalscheur followed the laboratory procedures, and the instrument was working properly. Harding testified that the machine's proper function was evident from the results of calibration checks run throughout the course of the tests. Harding said, "[t]he calibration checks that are analyzed throughout the course of the analytical run read correctly, specifically and importantly, the two known samples that bracketed Mr. Griep's sample read within their accepted range." Harding opined that correctly running the sample through the testing instrument resulted in a reliable blood alcohol reading. Harding also opined that after reviewing the data, he came to an independent opinion that Griep's BAC was 0.152.22 And finally, it was Harding's opinion that laboratory procedures required notation of any irregularities with the sample, and there had been no such notation by the analyst.
¶ 47. Consistent with Williams and Barton, the pre-Williams v. Illinois law of this jurisdiction, Harding's testimony did not violate Griep's right of confrontation; accordingly, his testimony was properly admit[687]*687ted.23 Our Confrontation Clause jurisprudence begins with Williams. Williams set out a two-part framework to analyze the testimony of an expert witness, relying on forensic tests conducted by a non-testifying analyst, for Confrontation Clause violations. Williams, 253 Wis. 2d 99, ¶ 26. Williams provides that expert testimony based in part on tests conducted by a non-testifying analyst satisfies a defendant's right of confrontation if the expert witness: (1) reviewed the analyst's tests, and (2) formed an independent opinion to which he testified at trial. Id. We address each requirement of Williams' framework in turn.
1. Review
¶ 48. In both Williams and Barton, the analyst who conducted the testing was unavailable to testify at trial. Instead, the analysts' supervisors testified as expert witnesses about the independent opinions they formed. Williams, 253 Wis. 2d 99, ¶ 22; Barton, 289 Wis. 2d 206, ¶ 15. In both Williams and Barton, the supervisors conducted reviews in the ordinary course of laboratory procedures. Williams, 253 Wis. 2d 99, ¶ 22; see Barton, 289 Wis. 2d 206, ¶ 14.
¶ 49. Peer review generally involves examining the notes taken and data collected in the case to make sure the conclusions written in the report are correct. Williams, 253 Wis. 2d 99, ¶ 22. In Williams, the expert witness testified how peer review operates when testing for a controlled substance: she compared the graphical data yielded by the tests and graphs reflect[688]*688ing standard, known, values. Id., ¶ 23. The expert's comparison allowed her to conclude the sample being tested was a controlled substance. Id. In Barton, an arson case, the expert used graphical data called chromatograms from different stages of gasoline evaporation to conclude gasoline was present in charred wood samples. Barton, 289 Wis. 2d 206, ¶ 15. The expert in Barton compared the chromatograms of control samples with chromatograms of the samples from the arson case, similar to the expert's comparison in Williams. See id.
¶ 50. Here, Harding did not conduct a formal peer review of Kalscheur's tests. Instead, peer review was completed by Thomas Ecker, an advanced chemist at the laboratory. However, Harding completed the same examination as occurs in the formal peer review. Harding examined "[t]he same data that is available the day after the analysis for the person that reviewed the report when it went out and that is the chromatograms and the paperwork associated with the whole analytical run that Diane did on the 30th of August, 2007." In short, Harding reviewed the same data as the peer reviewer.
¶ 51. Our decisions indicate that the review necessary to protect a defendant's right of confrontation need not be formal peer review. Williams, 253 Wis. 2d 99, ¶ 20; Deadwiller, 350 Wis. 2d 138, ¶ 40. In Williams, we reasoned: "the presence and availability for cross-examination of a highly qualified witness, who is familiar with the procedures at hand, supervises or reviews the work of the testing analyst, and renders her own expert opinion is sufficient to protect a defendant's right to confrontation." Williams, 253 Wis. 2d 99, ¶ 20. Similarly, in Deadwiller, the expert witness's review of the out-of-state laboratory's DNA profile, [689]*689procedures, and quality control measures was sufficient to protect the defendant's right of confrontation.
¶ 52. Harding's review of Kalscheur's report, data, and notes fulfills the Williams review requirement because he reexamined the data. See Williams, 253 Wis. 2d 99, ¶¶ 22-23. Therefore, Harding's review was sufficient to protect Griep's right of confrontation, when combined with Harding's independent opinion.
2. Independent opinion
¶ 53. In both Williams and Barton, the expert witness offered his or her independent opinion based in part on the data provided by the non-testifying analyst and the expert witness's own expertise. See Williams, 253 Wis. 2d 99, ¶¶ 25-26; Barton, 289 Wis. 2d 206, ¶ 16. Williams and Barton also discussed the expert witnesses' qualifications and noted they were qualified to give an expert opinion based on the information before them. Williams, 253 Wis. 2d 99, ¶ 21; Barton, 289 Wis. 2d 206, ¶¶ 13, 16. We discussed the role of an independent opinion most thoroughly in Williams, where we stated that "one expert cannot act as a mere conduit for the opinion of another." Williams, 253 Wis. 2d 99, ¶ 19. However, we recognized that an expert may form an independent opinion based in part on the work of others without acting as a "conduit." Id., ¶ 25.
¶ 54. In Williams, the expert witness reviewed the tests done by another analyst, including the data and notes, and then formed her own opinion. Id. We concluded that the testifying expert's opinion was sufficiently independent to protect the defendant's right of confrontation, and was not a mere recitation of another analyst's conclusions. Id., ¶¶ 25-26. In Bar[690]*690ton, the expert offered his opinion based on his review of the entire file, including data similar to the chromatograms in this case. Barton, 289 Wis. 2d 206, ¶¶ 13-14. The court of appeals concluded the expert's testimony was his independent opinion. Id,., ¶ 13.
¶ 55. Here, Harding was qualified to present testimony on the laboratory procedures and come to an independent opinion regarding Griep's BAC. To arrive at his conclusion, Harding relied on his review of data collected by Kalscheur, other records compiled at the laboratory, and his own expertise. Pointing to Harding's lack of personal knowledge of Kalscheur's testing of Griep's blood sample, Griep argues that Harding's opinion could not have been independent. However, we held in Williams, and the court of appeals held in Barton, that it was acceptable that the analyst's report, data, and notes were the factual bases of the expert witness's opinion, in addition to the witness's own professional expertise. Williams, 253 Wis. 2d 99, ¶ 25; Barton, 289 Wis. 2d 206, ¶ 13. Williams and Barton conclude that an expert witness need not have personal knowledge of the forensic tests, as long as the witness's opinion is reached independently and is not merely a recitation of another's conclusions. See Williams, 253 Wis. 2d 99, ¶ 25; Barton, 289 Wis. 2d 206, ¶¶ 13, 16. In each case, the expert witness rendered an independent opinion by reviewing data and notes from the analyst and the expert testified as to the general procedures for preparing and testing samples.24 Williams, 253 Wis. 2d 99, ¶ 25; Barton, 289 [691]*691Wis. 2d 206, ¶ 14. Harding conducted the same type of review and based his opinion on the same type of records and personal expertise as the expert witness did in Williams and Barton, and his opinion is similarly independent.
¶ 56. Harding reviewed Kalscheur's test results and other relevant laboratory records and he testified as to his independent opinion. In accordance with Williams and Barton, Harding's testimony did not violate Griep's right of confrontation. Williams, 253 Wis. 2d 99, ¶ 26; Barton, 289 Wis. 2d 206, ¶ 20.
III. CONCLUSION
¶ 57. We conclude that Harding's review of Griep's laboratory file, including the forensic test results of an analyst who was unavailable for trial, to form an independent opinion to which he testified did not violate Griep's right of confrontation. Williams, 253 Wis. 2d 99, ¶ 26; Barton, 289 Wis. 2d 206, ¶ 20. Accordingly, we affirm the court of appeals decision that affirmed the circuit court's admission of Harding's testimony.
By the Court. — The decision of the court of appeals is affirmed.
¶ 58. DAVID T. PROSSER, J., withdrew from participation.