Because there was no showing that the witness was permanently ill, the defendant was denied the constitutional right to confrontation by the court allowing the use of the witness’s deposition. Sheehan v. State, 65 Wis. 2d 757, 223 N.W.2d 600 (1974). Whether a witness’s refusal on 5th amendment grounds to answer otherwise permissible questions violates the defendant’s right to confrontation must be determined from the whole record. West v. State, 74 Wis. 2d 390, 246 N.W.2d 675 (1976). Admission of double hearsay did not violate the defendant’s right to confront witnesses. State v. Lenarchick, 74 Wis. 2d 425, 247 N.W.2d 80 (1976). Introduction into evidence of a victim’s hospital records unsupported by testimony of the treating physician did not violate the defendant’s right of confrontation and cross-examination. State v. Olson, 75 Wis. 2d 575, 250 N.W.2d 12 (1977). The trial court did not deny the defendant’s right of confrontation by forbidding cross-examination of the sole prosecution witness as to the witness’s history of mental illness, since no showing was made that the history was relevant to the witness’s credibility. The right of confrontation is also limited by s. 904.03 if the probative value of the desired cross-examination is outweighed by the possibility of unfair or undue prejudice. Chapin v. State, 78 Wis. 2d 346, 254 N.W.2d 286 (1977). The defendant’s right of confrontation was not violated when preliminary examination testimony of a deceased witness was admitted at trial when the defendant had unlimited opportunity to cross-examine the witness and the testimony involved the same issues and parties as at trial. Nabbefeld v. State, 83 Wis. 2d 515, 266 N.W.2d 292 (1978). A defendant’s right to compulsory process did not require admission of an unstipulated polygraph exam. Lhost v. State, 85 Wis. 2d 620, 271 N.W.2d 121 (1978). The trial court did not err in favoring a witness’s right against self-incrimination over the compulsory process rights of the defendant. State v. Harris, 92 Wis. 2d 836, 285 N.W.2d 917 (Ct. App. 1979). The state’s failure to use the Uniform Extradition Act to compel the presence of a doctor whose hearsay testimony was introduced denied the accused’s right to confront witnesses and violated the hearsay rule, but the error was harmless. State v. Zellmer, 100 Wis. 2d 136, 301 N.W.2d 209 (1981). Medical records, as explained to the jury by a medical student, were sufficient to support a conviction and did not deny the right of confrontation. Hagenkord v. State, 100 Wis. 2d 452, 302 N.W.2d 421 (1981). The trial court properly denied a request to present a defense witness who refused to answer relevant questions during an offer of proof cross-examination. State v. Wedgeworth, 100 Wis. 2d 514, 302 N.W.2d 810 (1981). Admission of a statement by a deceased co-conspirator did not violate the right of confrontation. State v. Dorcey, 103 Wis. 2d 152, 307 N.W.2d 612 (1981). Cross-examination, not exclusion, is the proper tool for challenging the weight and credibility of accomplice testimony. State v. Nerison, 136 Wis. 2d 37, 401 N.W.2d 1 (1987). A defendant waives the right of confrontation by failing to object to the trial court’s finding of witness unavailability. State v. Gove, 148 Wis. 2d 936, 437 N.W.2d 218 (1989). A prosecutor who obtains an incriminating statement from a defendant is obliged to honor a subpoena and to testify at a suppression hearing if there is a reasonable probability that testifying will lead to relevant evidence. State v. Wallis, 149 Wis. 2d 534, 439 N.W.2d 590 (Ct. App. 1989). A defendant had no confrontation clause rights as to hearsay at a pretrial motion hearing. The trial court could rely on hearsay in making its decision. State v. Frambs, 157 Wis. 2d 700, 460 N.W.2d 811 (Ct. App. 1990). Allegations of professional misconduct against the prosecution’s psychiatric expert initially referred to the prosecutor’s office but immediately transferred to a special prosecutor for investigation and possible criminal proceedings were properly excluded as the subject of cross-examination of the expert due to the lack of a logical connection between the expert and prosecutor necessary to suggest bias. State v. Lindh, 161 Wis. 2d 324, 468 N.W.2d 168 (1991). The ability of a child witness to speak the truth or communicate intelligently are matters of credibility for the jury, not questions of competency to be determined by the judge. State v. Hanna, 163 Wis. 2d 193, 471 N.W.2d 238 (Ct. App. 1991). When a witness’s “past-recollection recorded statement” was admitted after the witness testified and was found “unavailable” as a result of having no current memory of the murder in question, there was an opportunity for cross-examination and the right to confrontation was not violated. State v. Jenkins, 168 Wis. 2d 175, 483 N.W.2d 262 (Ct. App. 1992). A defendant charged with trespass to a medical facility is entitled to compulsory process to determine if any patients present at the time of the alleged incident had relevant evidence. State v. Migliorino, 170 Wis. 2d 576, 489 N.W.2d 678 (Ct. App. 1992). An indigent may be entitled to have a court compel the attendance of an expert witness. It may be error to deny a request for an expert to testify on the issue of suggestive interview techniques used with a young child witness if there is a “particularized need” for the expert. State v. Kirschbaum, 195 Wis. 2d 11, 535 N.W.2d 462 (Ct. App. 1995), 94-0899. In this case, the defendant’s right to confrontation was violated when the trial court failed to give the jury a limiting instruction regarding out-of-court statements made by a nontestifying codefendant. State v. Mayhall, 195 Wis. 2d 53, 535 N.W.2d 473 (Ct. App. 1995), 94-0727. But see Gray v. Maryland, 523 U.S. 185, 118 S. Ct. 1151, 140 L. Ed. 2d 294 (1998); Samia v. United States, 599 U.S. ___, 143 S. Ct. 2004, 216 L. Ed. 2d 597 (2023). An accused has the right to be present at trial, but the right may be waived by misconduct or consent. A formal on-the-record waiver is favored, but not required. State v. Divanovic, 200 Wis. 2d 210, 546 N.W.2d 501 (Ct. App. 1996), 95-0881. The right to confrontation is not violated when the court precludes a defendant from presenting evidence that is irrelevant or immaterial. State v. McCall, 202 Wis. 2d 29, 549 N.W.2d 418 (1996), 94-1213. Evidence of 911 calls, including tapes and transcripts of the calls, is not inadmissible hearsay. Admission does not violate the right to confront witnesses. State v. Ballos, 230 Wis. 2d 495, 602 N.W.2d 117 (Ct. App. 1999), 98-1905. For a defendant to establish a constitutional right to the admissibility of proffered expert testimony, the defendant must satisfy a two-part inquiry determining whether the evidence is clearly central to the defense and the exclusion of the evidence is arbitrary and disproportionate to the purpose of the rule of exclusion, so that exclusion undermines fundamental elements of the defendant’s defense. Under the first part of the inquiry, a defendant must demonstrate that the proffered testimony satisfies each of the following four requirements: 1) the testimony of the expert witness meets the s. 907.02 standards governing the admission of expert testimony; 2) the expert testimony is clearly relevant to a material issue in the case; 3) the expert testimony is necessary to the defendant’s case; and 4) the probative value of the expert testimony outweighs its prejudicial effect. Under the second part of the inquiry, the court must determine whether the defendant’s right to present the proffered evidence is nonetheless outweighed by the state’s compelling interest to exclude the evidence. State v. St. George, 2002 WI 50, 252 Wis. 2d 499, 643 N.W.2d 777, 00-2830. Cross-examination of a highly qualified witness, who is familiar with the procedures used in performing the tests whose results are offered as evidence, who supervises or reviews the work of the testing analyst, and who renders the expert’s 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. State v. Williams, 2002 WI 58, 253 Wis. 2d 99, 644 N.W.2d 919, 00-3065. When the privilege against self-incrimination prevents a defendant from directly questioning a witness about his or her testimony, it may be necessary to prohibit that witness from testifying or to strike portions of the testimony if the witness has already testified. A defendant’s right of confrontation is denied in each instance that potentially relevant evidence is excluded. The question is whether the defendant could effectively cross-examine the witness. State v. Barreau, 2002 WI App 198, 257 Wis. 2d 203, 651 N.W.2d 12, 01-1828.