Def.'s Ex. 101, at 1. In addition to seeking PIP coverage, Diaz also sued Prieto on behalf of Brayan. The significant difference between the PIP form and Brayan's testimony became a central issue at trial. Prieto's counsel stressed the differences between Diaz's and Brayan's testimony and the PIP form; Diaz's counsel stressed that the PIP form was based on accounts from people who did not see the accident.1
¶ 5 During opening statements, Prieto's counsel referenced the PIP form over Diaz's counsel's objection. After opening, out of the presence of the jury, Diaz's counsel addressed Prieto's counsel's use of the PIP form in opening and moved to exclude any further reference to it:
Your Honor, in anticipation of today's trial, in defendant's opening he brought up some piece of evidence that I think he might try to bring up again.
One was a Personal Injury Protection application. ...
*821It's a first-party application and privilege is not waived when you submit something to first-party insurance. And, in fact, first-party insurance is not supposed to share the PIP file with defense without permission of plaintiff.
In this case, he somehow got a copy of the PIP application. This raises a number of concerns. The PIP application is a *409no-fault insurance application, meaning that the description of the accident has no bearing on whether or not you get benefits in a PIP application.
....
He wants to use this PIP application as a statement against interest of [Diaz]. ...
... [Because this is a privileged document,] even though he already referenced it in his opening, and I objected to it then, I would move to exclude any further reference to this Personal Injury Protection application.
1 Report of Proceedings (RP) (June 2, 2016) at 119-21. Prieto's counsel responded:
First of all, this document is not privileged. ... This is an application form for Personal Injury Protection benefits for Brayan's treatment.
....
There is no law that the PIP application is not to be shared with defense counsel. Plaintiff has not cited to you any authority. That's important to keep in mind.
The PIP insurance coverage is, in essence, a no fault benefit provided on the insurance policy insuring Ms. Prieto. Okay?
So it's her insurance company that's providing this benefit of medical coverage to Brayan. There is no law that certainly the plaintiff has cited that prevents that information to be shared with me or Ms. Prieto's insurance company.
Id. at 121-22. The court then took a voir dire examination of Diaz to establish her knowledge of the PIP form and who filled it out.
¶ 6 After voir dire, and after argument by counsel for both sides, the court concluded:
Well, it's sort of odd this particular statement ... we have a statement signed by a party and yet, so arguably, it's a statement by the party versus the agent speaking on her behalf, which what we have here is this statement on its face doesn't show that it was the agent.
*410Now, we have testimony that does show that it was an agent who spoke essentially or had the party's authority to write it, because she essentially signed it and handed it over.
So the Court is going to find, first, that it's not a privileged document. That in redacted form, it doesn't violate the motion in limine as to collateral source. I do find it's an admission against interest under the rule as cited.
It will be allowed and that's my ruling.
Id. at 134-35. A redacted version of the PIP application was admitted into evidence. See Def.'s Ex. 101. Prieto's counsel then used the application to cross-examine Diaz:
Q. And three weeks after [speaking with Brayan about the accident at the hospital], you signed what's been admitted as Exhibit 101, with a description of the accident. Correct?
A. I signed it when it was blank.
Q. Okay. And the description reads, "Vehicle was traveling on North Cedar when child on bike rode into road. There were two parked cars on the road, creating a blind spot for the driver. Child was struck and had right leg ran over."
Correct?
A. I didn't know - I didn't know about that.
Q. But that's what the description states. Correct?
A. Yes. But I guess they got that from the police report because if I would have known that they were going to write that on it, I would not have signed it because I'm not in agreement with that.
2 RP (June 3, 2016) at 298-99. Prieto's counsel also used the application to cross-examine Diaz's accident reconstructionist, to support Prieto's reconstructionist's expert opinion, and, in closing argument, to question Diaz's credibility. Use of the PIP form was extensive, and the PIP form was the primary exhibit in the case because the police report *822was excluded as substantive evidence at trial as hearsay.
¶ 7 The jury returned a defense verdict. The Court of Appeals reversed, holding the PIP application was work *411product and its admission was prejudicial, requiring a new trial. Barriga Figueroa v. Prieto Mariscal, 3 Wash. App. 2d 139, 414 P.3d 590 (2018). We granted Prieto's petition for review and denied the issues raised by Diaz. Barriga Figueroa v. Prieto Mariscal, 191 Wash.2d 1004, 424 P.3d 1214 (2018). Washington State Association for Justice Foundation filed an amicus brief.
ANALYSIS
I. Quasi-fiduciary relationship
¶ 8 Since 1993, the State of Washington has required all insurers to offer PIP coverage to all automobile liability policyholders. See LAWS OF 1993, ch. 242. PIP insurance is designed to provide the insured with an immediate source of payment for out-of-pocket expenses resulting from an automobile accident. PIP benefits are available to an insured without proof of fault, and a pedestrian injured in an automobile accident is statutorily defined as an "insured." RCW 48.22.005(5)(b)(ii). Brayan, therefore, was an insured under Prieto's PIP coverage. Id.; cf Matsyuk v. State Farm Fire & Cas. Co., 173 Wash.2d 643, 654 n.4, 272 P.3d 802 (2012).
¶ 9 Under Washington law, insureds and insurers are in a quasi-fiduciary relationship. See Van Noy v. State Farm Mut. Auto. Ins. Co., 142 Wash.2d 784, 793, 16 P.3d 574 (2001) ; Tank v. State Farm Fire & Cas. Co., 105 Wash.2d 381, 385-86, 715 P.2d 1133 (1986). This quasi-fiduciary "relationship exists not only as a result of the contract between insurer and insured, but because of the high stakes involved for both parties to an insurance contract and the elevated level of trust underlying insureds' dependence on their insurers." Tank, 105 Wash.2d at 385, 715 P.2d 1133.2 Thus the quasi-fiduciary relationship arises not only out of the contract but also out of the *412type of occurrences that are covered by insurance, the high stakes of insurance litigation, and the necessary trust and reliance that an insured places on its insurer. See Br. of Amicus Curiae Wash. State Ass'n for Justice Found, at 8 ("An insurer's duty to exercise good faith is not limited to its contractual obligation to pay benefits, but 'permeates the insurance arrangement.' " (quoting St. Paul Fire & Marine Ins. Co. v. Onvia, Inc., 165 Wash.2d 122, 129, 196 P.3d 664 (2008) )).
¶ 10 By making the PIP claim on the tortfeasor's insurance company, the insurance company is also the pedestrian's insurer. RCW 48.22.005(5)(b)(ii). Even without a contract, the PIP claimant is required to cooperate with the insurer or risk denial of coverage.
¶ 11 We hold that an insurer owes a pedestrian PIP insured the same quasi-fiduciary duties that it owes a named insured who purchases a policy. Specifically, the " 'insurer must deal fairly with an insured, giving equal consideration in all matters to the insured's interests.' " See Van Noy, 142 Wash.2d at 794-95, 16 P.3d 574 (emphasis omitted) (quoting Tank, 105 Wash.2d at 386, 715 P.2d 1133 ). This approach is consistent with our common law and the plain language of RCW 48.01.030, which requires insurers to act in "good faith, abstain from deception, and practice honesty and equity in all insurance matters." (Emphasis added.) With this quasi-fiduciary relationship in mind, we turn to the work product issue.
II. Work Product
¶ 12 The Court of Appeals found the PIP form was protected work product. We agree. The work product rule states:
[A] party may obtain discovery of documents and tangible things otherwise discoverable under subsection (b)(1) of this rule and prepared in anticipation of litigation or for trial by or *413for another party or by or for that other party's representative *823(including a party's attorney, consultant, surety, indemnitor, insurer, or agent) only upon a showing that the party seeking discovery has substantial need of the materials in the preparation of such party's case and that the party is unable without undue hardship to obtain the substantial equivalent of the materials by other means.
CR 26(b)(4). Where the insured was the policyholder, we have held work product protections apply. See Heidebrink v. Moriwaki, 104 Wash.2d 392, 396, 706 P.2d 212 (1985) ; Harris v. Drake, 152 Wash.2d 480, 490, 99 P.3d 872 (2004). Here, the insurance relationship exists as a matter of statute, not contract. Nonetheless, we find the overarching reasoning of Heidebrink and Harris applies because the specific parties are in a quasi-fiduciary relationship. As such, Diaz may reasonably expect her insurer to give equal consideration to her interests as its own and has an expectation of confidentiality in the forms she submits.
¶ 13 Heidebrink is the leading case interpreting the work product rule in Washington in the context of communications between insureds and their insurers. 104 Wash.2d at 396, 706 P.2d 212. We held there was a "reasonable expectation that the contents of statements made by the insured will not be revealed to the opposing party." Id. at 400, 706 P.2d 212. After a searching review of scholarship and case law in other jurisdictions, we concluded:
[T]he better approach to the problem is to look to the specific parties involved and the expectations of those parties. With these parties in mind, the scope of CR 26(b)(3)[3 ] should provide protection when such protection comports with the underlying rationale of the rule to allow broad discovery, while maintaining certain restraints on bad faith, irrelevant and privileged inquiries in order to ensure just and fair resolutions of disputes.
Id. at 399-400, 706 P.2d 212 (emphasis added). Therefore, in determining whether a statement is prepared in anticipation of litigation *414and therefore covered under CR 26(b)(4), we must look to the specific parties involved and the expectations of those parties, the rationale for the rule, and the need to restrain bad faith and intrusion into privileged materials. See also Harris, 152 Wash.2d at 489, 99 P.3d 872 (" Heidebrink requires examination of the relationship of the parties in each case.").
¶ 14 Subsequently, in Harris, we applied Heidebrink and held that work product protection applied to an insured's independent medical examination performed at the request of the PIP insurer, based on the specific parties and their expectations. Id. at 490-91, 99 P.3d 872. In doing so, the Harris court carefully scrutinized the parties' relationship-emphasizing that "the relationship between an insured and his or her insurer is sometimes adversarial, while at other times the interest of the insured and insurer are aligned. This dual relationship requires close examination, evaluating the specific positions of the insurer and insured in each instance." Id. at 489, 99 P.3d 872.
¶ 15 Analyzing the specific parties and their expectations here, as we must under Heidebrink and Harris, we emphasize there is a dual relationship between Diaz and Brayan and their insurer. As a tort plaintiff against the named insured, Diaz and Brayan's relationship with the insurer is adversarial. As a pedestrian PIP insured, they are in a quasi-fiduciary relationship with the insurer.4 As such, Diaz and Brayan reasonably expect their insurer to deal fairly with them *824and give equal consideration in all matters to their interests. *415¶ 16 Further, as Brayan's parent and natural guardian, Diaz went to a law firm for legal assistance. As part of providing that legal assistance, the law firm sent a PIP application form to the parties' shared insurance company. Diaz did not fill out the forms herself, and it cannot be seriously contended that she sought legal assistance merely to have help filling out forms-Prieto ran over her eight-year-old son's leg, seriously injuring him. That no lawsuit had been filed when Diaz prepared Brayan's PIP application is of no consequence; Diaz plainly signed the form in anticipation of litigation, in a lawyer's office, with assistance from the law firm ultimately suing Prieto. Indeed, in Heidebrink, we stated that had the statements been "made directly to the [insurance company's] selected attorney, it would obviously have been made in anticipation of litigation." 104 Wash.2d at 400, 706 P.2d 212. The statements were made in anticipation of litigation. Thus, we hold work product protections apply.
III. Prejudice
¶ 17 Having concluded it was error for the trial court to hold the document was not protected, we must next determine whether the trial court's error was of sufficient magnitude to necessitate a new trial. Prieto argues there is no prejudice because the evidence was cumulative and admission of cumulative evidence is harmless.
¶ 18 When a trial court makes an erroneous evidentiary ruling, the question on appeal becomes whether the error was prejudicial, for error without prejudice is not grounds for reversal. Driggs v. Howlett, 193 Wash. App. 875, 903, 371 P.3d 61 (2016) (citing Brown v. Spokane County Fire Prot. Dist. No. 1 , 100 Wash.2d 188, 196, 668 P.2d 571 (1983) ). Error will be considered prejudicial if it presumptively affects the outcome of the trial. James S. Black & Co. v. P&R Co ., 12 Wash. App. 533, 537, 530 P.2d 722 (1975). Improper admission of evidence constitutes harmless error if the evidence is cumulative. Hoskins v. Reich, 142 Wash. App. 557, 570, 174 P.3d 1250 (2008).
*416¶ 19 Prieto argues the evidence is cumulative because the statement as to how the accident happened, as stated in the PIP application, was cumulative of the trial testimony of Diaz's own accident reconstruction expert. Prieto argues, "Before the PIP application was admitted, the expert testified as to Brayan's 'explanation of how he rode that day, prior to being hit.' Therefore, the record at trial contains undisputed evidence that Brayan himself told his expert he rode into the street prior to being hit." Suppl. Br. of Pet'r at 19 (quoting 1 RP (June 2, 2016) at 167). We are not persuaded by this characterization of the evidence.
¶ 20 Prieto is correct that the expert stated Brayan rode in the street "prior to being hit," i.e., earlier that day, but that is not at issue. 1 RP (June 2, 2016) at 167. At issue is what happened immediately before Brayan was hit. Regarding that issue, the PIP form says "child on a bike rode into road " and due to a blind spot "was struck," which Prieto used to attack Diaz's version of the events. Def.'s Ex. 101, at 1 (emphasis added). Diaz said immediately before being hit Brayan was not riding, he was leaned over untangling his shoelace. The PIP form was not cumulative as Diaz's evidence strikingly differed.
¶ 21 Admission of the PIP form prejudiced Diaz.5 It was used extensively by Prieto's counsel throughout trial. It was used in opening; it was used to cross-examine Diaz and Diaz's accident reconstructionist; it was used to form opinions of the accident by an accident reconstructionist retained on behalf of Prieto; and it was used in closing argument to question Diaz's credibility. Further, when *825Prieto's counsel used the PIP form, he almost always emphasized *417the fact that it was signed by Diaz, thereby attributing the statements to her. Diaz did not make these statements; the legal assistant filled out the PIP form based on the police report. Crucially, the speculative statements in the police report were hearsay and the police report was inadmissible at trial for this reason.
¶ 22 Prieto's counsel repeatedly claimed throughout trial that Brayan was hit after he rode his bicycle between two parked cars and into the road. Prieto asserts Diaz's accident reconstructionist's testimony supports this claim but, as discussed above, it does not-the PIP form served as the basis for the claim, and the PIP form was therefore not cumulative. The trial court erroneously admitted the PIP form, and its admission prejudiced Diaz.
CONCLUSION
¶ 23 The PIP form was work product in light of the specific parties and their expectations, and its admission prejudiced Diaz. We affirm the Court of Appeals and remand for a new trial.
WE CONCUR:
Fairhurst, C. J.
Owens, J.
Stephens, J.
Wiggins, J.
Yu, J.