When people think about medical malpractice lawsuits, they often picture a doctor testifying in a courtroom. But in reality, that’s only one stage of expert involvement. Way before a case reaches trial, attorneys rely on medical experts to evaluate claims, identify strengths and weaknesses, and determine whether litigation is appropriate. Treating expert involvement as a single decision can lead to unnecessary costs, delays, and missed opportunities.
Instead, many medical malpractice cases follow a chain. A physician may first perform an initial merit review to determine whether a claim has legal and medical support. If the case appears promising, another physician may provide a second opinion to strengthen or challenge the initial assessment. Only after the case moves forward does an attorney typically retain a testifying expert who prepares reports, gives depositions, and appears at trial.
Understanding these different levels of expert involvement is important because each serves a different purpose, has different costs, and has different legal implications. Choosing the right level at the right time can save both time and money while helping attorneys build stronger cases.
Tier One: Merit Review (Case Screening)
The first level of expert involvement occurs before or shortly after a lawsuit is filed. At this stage, an attorney asks a physician to review a limited set of medical records to determine whether the case appears to have merit.
The physician’s role is relatively straightforward. They evaluate whether the healthcare provider may have departed from the accepted standard of care and whether that departure likely caused the patient’s injury. If the physician concludes that no negligence occurred, the attorney may decide not to pursue the case. If the physician believes malpractice may have occurred, the attorney can continue investigating.
Because this review is intended to help attorneys decide whether a case should move forward, the work product is often informal. Many merit reviews result in a phone call, meeting, or brief written opinion rather than a lengthy expert report. Attorneys frequently prefer to keep these early discussions limited because consulting experts who are not expected to testify generally receive greater protection from discovery under the Federal Rules of Civil Procedure.
Merit reviews also play an important role in states that require an affidavit or certificate of merit before a medical malpractice lawsuit can proceed. Although the exact requirements vary by state, these laws are designed to discourage frivolous litigation by requiring a qualified medical professional to certify that the claim has a reasonable basis before significant court resources are invested.
From a cost perspective, Tier One is typically the least expensive level of expert involvement. Physicians usually spend only a few hours reviewing records, making it an efficient way for attorneys to determine whether additional investment is justified.
Tier Two: Peer Review or Second Opinion
The second level is where things start to get a little confusing, mostly because the phrase peer review means different things depending on who’s using it.
In healthcare, peer review often refers to a hospital evaluating the quality of care provided by one of its physicians. Insurance companies also use the term when another doctor reviews whether a treatment was medically necessary. Neither of those is what attorneys are usually talking about in medical malpractice litigation.
In the litigation context, a peer review is best thought of as a second opinion. Instead of relying on one physician’s assessment, a law firm may ask another expert, often someone in the same specialty, to independently review the records. The goal isn’t to create another lengthy report. It’s to answer a simple question: Does another qualified physician reach the same conclusion?
That extra review can be incredibly valuable. If both physicians independently conclude that the standard of care was breached, attorneys gain confidence before investing significant time and money into litigation. On the other hand, if the second physician disagrees with the first, it gives the legal team an opportunity to identify weaknesses before those issues surface during discovery or at trial.
Not every firm treats this as a completely separate stage. Some combine it with the initial merit review, while others don’t seek another opinion until the case becomes more serious. There isn’t one universal process. Instead, the decision usually depends on the complexity of the medicine, the potential damages involved, and how confident the attorney feels after the first review.
The important takeaway is that Tier Two is less about producing new evidence and more about reducing uncertainty. Spending a little more time early in the case can prevent much larger problems later.
Tier Three: Retained Testifying Expert
This is the stage most people imagine when they hear the words expert witness. Once a case moves into active litigation, attorneys often retain one or more physicians to serve as testifying experts. Unlike consulting experts, these physicians are expected to publicly defend their opinions through written reports, depositions, and trial testimony.
Their responsibilities are much broader than those of a physician performing a merit review. A retained expert reviews the complete medical record, studies the relevant medical literature, prepares a formal report explaining each opinion, meets with attorneys throughout the case, answers questions during depositions, and, if necessary, testifies before a judge and jury.
Because of those responsibilities, Tier Three is by far the most expensive level of expert involvement. Experts typically charge separately for reviewing records, writing reports, meeting with attorneys, giving depositions, and appearing in court. Depending on the physician’s specialty and experience, those costs can add up quickly.
Retained experts are also subject to much greater disclosure requirements. Under Rule 26 of the Federal Rules of Civil Procedure, they generally must provide a written report that includes their opinions, the facts and data they relied on, their qualifications, publications, prior testimony, and compensation. That information allows the opposing side to evaluate both the expert and the opinions they intend to offer.
Even after an expert is disclosed, the court still acts as a gatekeeper. Under Daubert v. Merrell Dow Pharmaceuticals, judges must determine whether expert testimony is reliable before allowing a jury to hear it. More recently, amendments to Federal Rule of Evidence 702 that took effect in December 2023 reinforced that responsibility, emphasizing that judges, not juries, must decide whether the expert’s opinions satisfy the rule’s reliability requirements before they are admitted.
For attorneys, this means hiring an impressive physician isn’t enough. The expert’s opinions must also be supported by reliable methods and a clear explanation of how they reached their conclusions.
The “Peer Review” Problem: Why Terminology Matters
One of the biggest sources of confusion in medical expert work is the phrase “peer review.” Depending on the context, it can describe completely different processes.
In a hospital setting, peer review usually refers to an internal quality improvement process. Hospitals may review physician performance, patient outcomes, or whether care met internal standards. These reviews are generally designed to improve healthcare quality rather than support litigation.
Insurance companies also use peer review in a different way. In that context, a physician may evaluate whether a treatment or procedure was medically necessary for coverage purposes.
Neither of these should be confused with litigation-focused expert review. When attorneys discuss peer review in a malpractice case, they are typically referring to another physician evaluating the medical issues involved in the claim. This physician may confirm the initial expert’s opinion, identify weaknesses in the case, or provide another perspective before the firm commits significant resources.
The distinction matters because the purpose of each review is different. A hospital peer review focuses on improving healthcare systems. An insurance review focuses on medical necessity. A litigation review focuses on evaluating potential legal claims. For attorneys handling medical malpractice cases, understanding these differences helps ensure that the right expert is involved at the right stage.
Wrongful Death: How the Expert Ladder Changes
Wrongful death cases demonstrate why expert involvement cannot be treated as a one-size-fits-all process. A wrongful death claim occurs when a person’s death is allegedly caused by another party’s negligence or wrongful act. In medical malpractice cases, the central question is often not simply whether a healthcare provider made a mistake. The larger question is whether that mistake actually caused the patient’s death.
This distinction makes causation one of the most heavily contested issues in wrongful death litigation. For example, imagine a patient arrives at a hospital with symptoms of a serious condition. The medical team fails to recognize the condition quickly enough, and the patient later dies. The dispute may not be whether the diagnosis was delayed. Instead, experts may need to determine whether earlier treatment would have changed the outcome.
Medical experts analyze issues such as:
- The patient’s medical history
- Treatment decisions
- Laboratory results
- Imaging studies
- Timing of symptoms and interventions
Depending on the case, attorneys may need experts from multiple fields. A physician may explain whether the standard of care was violated, while other experts may evaluate damages. For example:
- A cardiologist may explain whether a delayed diagnosis contributed to death.
- A pathologist may analyze the cause of death.
- An economist may calculate lost income.
- A vocational expert may evaluate future earning capacity.
Wrongful death cases can also involve the “loss of chance” doctrine, which some states recognize. This legal theory allows recovery when medical negligence reduces a patient’s chance of survival, even if survival was never guaranteed. However, states differ significantly in whether they recognize this approach and how they apply it. Because medical malpractice law is largely state-specific, attorneys must understand the rules of the jurisdiction where the case is filed.
The expert ladder in wrongful death cases often expands depending on the complexity of the medical issues and damages involved. A relatively straightforward case may require only a small number of experts, while a complex case involving multiple conditions may require a much broader team.
Birth Injury: Why Some Cases Require an Entire Expert Team
Birth injury cases represent one of the most complex areas of medical malpractice litigation. Unlike many other malpractice cases, birth injury cases often involve questions about events occurring before, during, and immediately after delivery. Because injuries may affect a child for their entire life, the medical, legal, and financial stakes can be extremely high.
Common birth injury claims include:
- Hypoxic-ischemic encephalopathy (HIE), a type of brain injury associated with reduced oxygen supply
- Cerebral palsy claims related to complications during delivery
- Brachial plexus injuries involving nerves in the shoulder and arm
- Delayed emergency cesarean sections
- Failure to properly interpret fetal heart monitoring
The complexity of these cases means one expert is rarely enough. A birth injury case may involve:
- An OB/GYN to evaluate pregnancy and delivery decisions
- A labor and delivery nurse to evaluate nursing care
- A neonatologist to assess newborn care
- A pediatric neurologist to evaluate neurological outcomes
- A neuroradiologist to interpret brain imaging
- A life care planner to estimate future medical needs
- An economist to calculate future financial losses
One of the most disputed issues in birth injury cases is timing. When a child experiences neurological injury, experts may disagree about when the injury occurred. Plaintiff experts may argue that the injury occurred during labor because medical intervention was delayed. Defense experts may argue that the injury happened earlier due to genetic factors, infection, or other causes unrelated to delivery.
Brain imaging, particularly MRI findings, often becomes a major part of this debate. Neuroradiologists may analyze imaging to help determine when an injury likely occurred and whether the findings support one explanation over another.
Birth injury cases also create unique timing challenges because the injured person is often a minor. Many states have special rules that affect when a lawsuit must be filed, meaning cases may begin years after the original delivery. By that point, organizing older medical records can become a major challenge.
Bottom line. Expert involvement in malpractice is a ladder, not a single hire. Merit review screens cases cheaply; a second opinion reduces uncertainty; retained experts carry the full litigation burden and the full cost. Wrongful death and birth injury cases often require multiple specialists at each tier.