The use of expert witnesses in Arizona is subject to the Arizona Rules of Evidence. At Stone Rose Law, we know how and when to call on expert witness testimony in personal injury matters.
Here, we cover who can be an expert witness in a civil case, some of the evidentiary questions expert witness testimony can help with, and how an expert witness can bolster your claim for compensation in settlement or at trial.
If you would like to discuss your personal injury case with one of our lawyers, call us at (480) 531-3025.
Who Can Be an Expert Witness?
Witness testimony can come from lay witnesses and expert witnesses. So, the first issue to consider is what qualifies a witness as an expert.
Arizona Rule of Evidence 702 defines an expert witness as a person qualified by knowledge, skill, experience, training, or education to give testimony, including objective opinions, if the party presenting the expert witness can demonstrate to the court, by a preponderance of the evidence, that:
- The expert’s scientific, technical, or clinical experience, or other specialized knowledge, will help the trier of fact (usually the jury) to understand the evidence or to determine a fact in issue;
- The witness testimony is based on sufficient facts or data, and is the product of reliable principles and methods; and
- The expert’s opinion reflects a reliable application of the principles and methods to the facts of the case.
Fundamentally, the role of a lay witness in the settlement or litigation process is to give testimonial evidence of first-hand experience or observation. An expert witness, by contrast, helps the judge or jury understand evidence that might otherwise be too complex by providing specialized knowledge in a way that a non-expert can understand.

In a personal injury case, an expert witness is an individual with specialized knowledge, training, or experience relevant to personal injury evidence. Examples of personal injury expert witnesses include:
- Doctors, nurses, and other medical experts who can testify about the nature and extent of your injuries, the care and treatment you have received, your long-term prognosis, and how your injuries can be expected to affect your future medical expenses.
- Accident reconstruction experts who use physics, engineering, and digital modeling to explain how an accident happened and how the resulting vehicle accident caused your injuries.
- Economic experts who can testify about the financial impact your injuries will have on your lost wages claims and your potential future earnings.
- Vocational experts who can evaluate whether your injuries limit your ability to work and the effect of your injuries on your future employment opportunities.
- Mental health professionals, like psychologists or psychiatrists, who, in cases involving emotional trauma, can testify about your pain and suffering and the impact of the injury on your mental health.
What Can an Expert Witness Testify About?
When it comes to what an expert witness in personal injury claim may testify about, some key differences exist between a lay witness and an expert witness:
- Generally, a lay witness is limited to opinions that are rationally based on the witness’s own perception and do not require specialized knowledge.
- In contrast, an expert witness does not have to have witnessed the accident, but, based on professional expertise, can provide independent information on an aspect of a personal injury claim.
- A lay witness is generally unable to offer an opinion about the evidence at issue in the case. But experts are permitted to do so.
The ability of the expert witness to offer testimony not based on personal observation or experience, or to offer opinion testimony, is not unrestricted. Here, the Arizona Rules of Evidence provide important guidance.
For example, under Arizona Rule of Evidence 703, an expert witness may base an opinion on facts or data that the expert has been made aware of, so long as other experts in the same field would reasonably rely on those facts or data.
This is true even if those facts or data would otherwise not be admissible at trial. But if the facts or data are inadmissible on their own, then the expert can disclose them only if their value in helping the jury evaluate the opinion substantially outweighs any prejudicial effect(s).
Also, under Arizona Rules of Evidence 705, unless the court orders otherwise, an expert witness may state an opinion and give the reasons for it without first testifying to the underlying facts or data. However, the expert may be required to disclose those facts or data on cross-examination.
Expert witnesses can be particularly helpful in cases where:
- Determining liability is disputed based on different interpretations by the parties involved. This can include an injury-causing event or, in cases of product liability, a defective design or manufacturing.
- Educating the jury on complex technical or scientific matters.
- Professional standards are the basis of establishing a negligence claim. For example, in Arizona medical malpractice cases, expert testimony is generally required to establish the applicable standard of care and causation.
- To prove the severity of your injuries and the technical details of your medical treatment.
- To quantify your past and anticipated future financial losses and medical costs.
- To determine the fault of the defendant in complex cases, such as an action alleging that you suffered an illness or chronic medical condition.
- Physical evidence for how the accident occurred is limited, eyewitness testimony is unavailable, or both.
How Does Your Personal Injury Lawyer Use an Expert Witness?
Using an expert witness in an Arizona personal injury claim, whether in settlement negotiations or at trial, takes considerable preparation by your personal injury attorney. Here is an overview of the expert witness process.
Selecting the Expert
Expert witness testimony is not required in all personal injury legal proceedings. Therefore, the starting point is your lawyer’s determination as to whether expert witness testimony is needed in your case. This requires a comprehensive analysis of your personal injury case, identifying areas where expert testimony can be key to resolving any evidentiary dispute(s).
If your lawyer decides that expert testimony is necessary, then they will seek out a qualified expert, using the criteria established in the Arizona Rules of Evidence. This may involve consulting professional networks, researching experts with a proven track record, or using referrals from colleagues.
Your attorney then carefully evaluates the expert’s qualifications, professional experience, and prior testimony history to see that his or her expertise aligns with your evidentiary requirements.
Preparing the Expert for Testimony
Expert testimony is not a hit-or-miss matter, but requires thorough preparation so the expert will clearly understand the matter at issue and the expert’s role in presenting facts, data, and opinions to the jury.
Your attorneys will work closely with the expert to review the relevant legal standards, the specific facts of your case, and expected questions the expert will be asked during cross-examination. This preparation will often consist of practice examinations and cross-examinations.
Can Your Personal Injury Claim Benefit From Expert Witness Testimony?
In Arizona personal injury cases, experts provide testimony that can significantly affect the compensation you may recover. Whether you’re dealing with a car accident, a slip and fall injury, a product liability claim, or a medical malpractice action, having the right expert witnesses can play a vital role in explaining complex issues and proving your case in a way that lay witness testimony alone cannot.
But selecting and preparing an expert witness for your personal injury claim is not always simple, and not all expert witnesses are the same. The law firm you choose must make informed decisions about when they are needed, make a comprehensive evaluation on how to select them, and how to best prepare them.
At Stone Rose Law, we understand the critical role that expert witnesses play in Arizona personal injury cases. With our experience as personal injury settlement negotiators and trial litigators, we provide invaluable assistance in selecting quality expert witnesses and leveraging expert witnesses to strengthen your case.
To learn more about our personal injury legal representation services, and to schedule a free consultation with one of our experienced team of Arizona personal injury attorneys, call us at (480) 531-3025. You can also use our online contact form to schedule a free initial consultation with us.
The post When to Hire an Expert Witness in a Personal Injury Case appeared first on Stone Rose Law.
