The opinion of the court was delivered by: Bales, Vice Chief Justice.
¶ 1 This case concerns the interpretation and constitutionality of A.R.S. § 12–2604, which sets requirements for experts who testify about the appropriate standard of care in medical malpractice actions.
¶ 2 Seventeen-year-old Tara Baker was treated for blood clots by Dr. Brenda Wittman, an employee of University Physicians Healthcare and the Arizona Board of Regents. Ms. Baker later died and her father, Mr. Robert Baker, brought this wrongful-death action alleging medical malpractice against Dr. Wittman, her spouse, and her employers (collectively "UPH").
¶ 3 Dr. Wittman is certified by the American Board of Pediatrics in pediatrics and in pediatric hematology-oncology. The American Board of Medical Specialties ("ABMS") recognizes pediatrics as a specialty and pediatric hematology-oncology as a subspecialty of pediatrics. To testify about the standard of care owed to Ms. Baker by Dr. Wittman, Mr. Baker disclosed Dr. Robert Brouillard as his expert. Dr. Brouillard is certified by the American Board of Internal Medicine in internal medicine and in hematology and medical oncology. The ABMS recognizes internal medicine as a specialty and hematology and medical oncology as subspecialties of internal medicine.
¶ 4 UPH moved for summary judgment, arguing that Dr. Brouillard was not a qualified expert under § 12–2604. The statute provides in part:
A. In an action alleging medical malpractice, a person shall not give expert testimony on the appropriate standard of practice or care unless the person is licensed as a health professional in this state or another state and the person meets the following criteria:
1. If the party against whom or on whose behalf the testimony is offered is or claims to be a specialist, specializes at the time of the occurrence that is the basis for the action in the same specialty or claimed specialty as the party against whom or on whose behalf the testimony is offered. If the party against whom or on whose behalf the testimony is offered is or claims to be a specialist who is board certified, the expert witness shall be a specialist who is board certified in that specialty or claimed specialty.
2. During the year immediately preceding the occurrence giving rise to the lawsuit devoted a majority of the person's professional time to either or both of the following:
(a) The active clinical practice of the same health profession as the defendant and, if the defendant is or claims to be a specialist, in the same specialty or claimed specialty.
(b) The instruction of students in an accredited health professional school or accredited residency or clinical research program in the same health profession as the defendant and, if the defendant is or claims to be a specialist, in an accredited health professional school or accredited residency or clinical research program in the same specialty or claimed specialty.
A.R.S. § 12–2604(A)(1)–(2).
¶ 5 The trial court granted UPH's motion for summary judgment. Determining that the relevant specialty was pediatric hematology, the trial court ruled that Dr. Brouillard was not a qualified expert because he, unlike Dr. Wittman, was not certified in that specialty. (Although the attorneys and the trial court referred to "pediatric hematology," the correct term is "pediatric hematology-oncology.") The court also rejected Mr. Baker's constitutional challenges to the statute.
¶ 6 The court of appeals agreed that Dr. Brouillard was not qualified but reversed the trial court's decision in part. It ruled that the word "specialty" in § 12–2604 refers to one of the twenty-four specialty boards that make up the ABMS, rather than subspecialties such as pediatric hematology-oncology. Baker v. Univ. Physicians Healthcare, 228 Ariz. 587, 590–91 ¶¶ 8, 13, 269 P.3d 1211, 1214–15 (App.2012). The court declined to follow Awsienko v. Cohen, in which another appellate panel suggested that "specialty" includes ABMS subspecialties. 227 Ariz. 256, 258, 260 ¶¶ 9, 17–18, 257 P.3d 175, 177, 179 (App.2011). Under the definition adopted by the court of appeals here, Dr. Brouillard was not qualified as an expert because he was not board certified in pediatrics, the ABMS specialty in which Dr. Wittman was board certified. Baker, 228 Ariz. at 591 ¶ 11, 269 P.3d at 1215. Remanding, the court of appeals instructed the trial court to give Mr. Baker time to find another expert who is board certified in pediatrics. Id. at 593 ¶ 25, 269 P.3d at 1217.
¶ 7 We granted review to address issues of statewide importance regarding the application of § 12–2604. We have jurisdiction under Article 6, Section 5(3) of Arizona's Constitution and A.R.S. § 12–120.24.
¶ 8 We interpret statutes to give effect to the legislature's intent, looking first to the statutory language itself. State v. Williams, 175 Ariz. 98, 100, 854 P.2d 131, 133 (1993). When the language is clear and unambiguous, and thus subject to only one reasonable meaning, we apply the language without using other means of statutory construction. State v. Gomez, 212 Ariz. 55, 57 ¶ 11, 127 P.3d 873, 875 (2006). If, however, the language is ambiguous, " 'we consider the statute's context; its ... subject matter, and historical background; its effects and consequences; and its spirit and purpose.' " Id. (quoting Hayes v. Cont'l Ins. Co., 178 Ariz. 264, 268, 872 P.2d 668, 672 (1994)).
¶ 9 The general intent of § 12–2604 is clear: in a medical malpractice action, only physicians with comparable training and experience may provide expert testimony regarding whether the treating physician provided appropriate care. The statute, however, is ambiguous regarding its application to particular cases. If a treating physician is or claims to be a board-certified specialist, the statute provides that a testifying expert must be board certified in the same specialty. A.R.S. § 12–2604(A). But the statute does not define the terms "specialist" or "board certified," and Arizona law does not otherwise provide general definitions for these terms. A physician need not be considered a specialist in order to practice in a certain area of medicine, and physicians who specialize may provide medical treatment outside their specialty. Moreover, different specialists may be prepared by training and experience to treat the same medical issue for a particular patient. Finally, physicians may hold multiple certifications from different certifying bodies.
¶ 10 Applying § 12–2604 requires us to interpret its terms in a way that comports with the legislature's intent and provides guidance to those affected by its provisions. We first consider the statute's application to testimony about the "appropriate standard" of care and then consider the meaning of the terms specialist, specialty, and board certified.
¶ 11 The statute sets qualifications for witnesses who may provide "expert testimony on the appropriate standard of practice or care." A.R.S. § 12–2604(A) (emphasis added). This language informs our interpretation of the other statutory provisions specifying qualifications for expert witnesses.
¶ 12 In medical malpractice cases, plaintiffs must show that a health care provider breached the appropriate standard of care and the breach resulted in injury. Id. § 12–563. The standard of care, however, necessarily depends on the particular care or treatment at issue. See id. § 12–563(1) (describing the standard of care broadly, as "that degree of care, skill and learning expected of a reasonable, prudent health care provider in the profession or class to which he belongs within the state acting in the same or similar circumstances"). Thus, only if the care or treatment involved a medical specialty will expertise in that specialty be relevant to the standard of care in a particular case.
¶ 13 With regard to treating physicians who are or claim to be specialists, § 12–2604(A)(1) requires testifying experts to "specialize[ ] ... in the same specialty or claimed specialty as the party against whom or on whose behalf the testimony is offered." This requirement, however, presumes that the care or treatment at issue was within the specialty of the treating physician. If a treating physician practices outside his or her specialty, the statute does not require a testifying expert to possess qualifications in an irrelevant medical specialty, nor would any such requirement make sense. See Baker, 228 Ariz. at 594 ¶ 28, 269 P.3d at 1218 (Eckerstrom, J., concurring) ("[E]xpert witnesses need not mirror those specialties of the defendant physician that are not pertinent to the relevant injury or procedure."); Woodard v. Custer, 476 Mich. 545, 719 N.W.2d 842, 849–50 (2006) (reasoning that a statute similar to § 12–2604 should not be read to require irrelevant specialties and board certifications); cf. Taylor v. DiRico, 124 Ariz. 513, 518–19, 606 P.2d 3, 8–9 ...