A practical guide for plaintiff and defense attorneys on evaluating credentials, assessing objectivity, identifying red flags, and asking the right questions before retaining anyone.

The construction expert witness you retain may be the single most consequential decision you make in a construction defect case. A technically sound expert with clear communication skills, demonstrated objectivity, and genuine field experience will strengthen your case at every stage — from shaping discovery to holding up under the most aggressive cross-examination at trial.

Yet many attorneys approach expert selection reactively — reaching out to a familiar name a few weeks before the expert designation deadline and hoping for the best. This guide is intended to help you think more systematically about how to evaluate and choose a construction expert witness, regardless of which side of a dispute you represent.

The criteria below apply equally to plaintiff and defense engagements. A good construction expert witness is good precisely because their analysis holds up from any angle.

The first thing to verify is whether the expert holds the professional credentials actually relevant to the disputed construction. In California, this begins with the California Contractors State License Board (CSLB). An expert offering opinions about defective electrical work should hold — or have held — the appropriate California electrical contractor’s license. An expert opining on HVAC installation defects should have demonstrable credentials in mechanical contracting.

One important nuance: credentials on paper must be matched by actual field experience. A licensed contractor who spent most of their career in an office, or whose license was obtained decades ago with no recent field work, may struggle to speak credibly about current construction practices, materials, and methods.

There is no substitute for an expert who has actually performed — not just supervised, not just inspected — the type of construction at the center of the dispute. An expert who has personally run wire, installed ductwork, roughed in plumbing, or poured concrete foundations brings something to the analysis that no amount of academic study replicates.

“The most effective construction expert witnesses are those who can say ‘I have done this work’ — not merely ‘I have studied this work.’ That distinction comes out clearly on cross-examination.”

When evaluating field experience, look for specificity. An expert with general commercial construction experience may not be well-suited to opine on residential framing defects. For MEP system disputes in particular, the depth of field experience matters enormously — a licensed mechanical contractor who has installed hundreds of commercial systems is a different expert from an engineer who designed them from an office.

Key questions to investigate:

• Does the expert’s field experience match the specific type of construction at issue?
• Did the expert personally perform — not merely supervise — the relevant work?
• Is the experience current enough to speak to applicable code versions?
• Does commercial vs. residential experience align with your project type?
• Has the expert worked in the relevant California geographic market?

This criterion is the one most frequently underweighted by attorneys retaining experts — and the one opposing counsel will most aggressively exploit. An expert who consistently testifies for only one side, uses advocacy language in their marketing materials, or cannot articulate the weaknesses in your case is a liability, not an asset.

The most meaningful indicator of objectivity is whether the expert accepts engagements from both plaintiff and defense counsel. When you first speak with a prospective expert, describe the facts of your case and ask them directly: what weaknesses do you see in the technical narrative? An expert who engages seriously with this question is demonstrating the objectivity that will make them effective at trial.

A construction expert’s report is the document that will be scrutinized by opposing counsel, their own expert, and potentially the court. Under California law following Sargon Enterprises, Inc. v. University of Southern California (2012), expert testimony not based on a reliable methodology can be excluded entirely.

Before retaining any construction expert, ask to review a sample report from a prior engagement — with identifying information redacted. What you are looking for is a report that clearly distinguishes between facts (what was observed), methodology (how it was evaluated), and opinions (the expert’s conclusions). The report should identify the specific code provisions, industry standards, and manufacturer requirements that establish the standard of care, cite them by edition and section, and explain precisely how observed conditions deviate from those standards.

“A vague opinion is a vulnerable opinion. The more precisely an expert’s conclusion can be traced to a specific observation, a specific standard, and a specific deviation, the harder it is to impeach.”

Technical expertise and litigation experience are not the same thing. An experienced testifying expert knows how to listen carefully to a question before answering, how to respond to compound or misleading questions without creating admissions, and how to maintain composure when opposing counsel becomes aggressive.

The most technically correct opinion in the world has no value if a juror cannot understand it. The expert’s job is not to demonstrate how much they know. It is to translate what they know into language that makes the technical issues as clear and simple as the evidence honestly allows.

“Ask the expert to explain one of the core technical issues in your case as if they were explaining it to someone with no construction background. What you hear in that moment is a preview of what the jury will hear.”

Construction defect litigation moves on tight deadlines. Expert designation deadlines, discovery cut-offs, and trial dates do not flex for a busy expert who is double-booked. Before retaining anyone, have a direct conversation about the expert’s current workload, their capacity to prioritize your matter, and their specific availability for site inspection, report preparation, and deposition during the relevant windows in your case schedule.

Beyond the affirmative criteria above, there are specific warning signs that should give any attorney pause before retaining a construction expert witness. These are patterns that opposing counsel will find and use.

The initial consultation is your opportunity to evaluate the expert against the criteria above. The following questions are designed to surface the information that matters.

Use this reference when evaluating any construction expert before retention.

• Holds relevant California CSLB license classification(s)
• Has personally performed the relevant type of construction work
• Field experience matches the specific construction type at issue
• Accepts engagements from both plaintiff and defense counsel
• No advocacy language in public materials or marketing
• Honestly identifies weaknesses in your case during the initial call
• Sample report clearly distinguishes facts, methodology, and opinions
• Codes cited by specific edition and section in reports
• Deposition or trial testimony experience confirmed
• Can explain technical issues clearly to a non-technical audience
• Available within your case schedule and designation deadlines
• Responsive and professionally organized from first contact

Danliv, Inc. is a California-licensed construction consulting firm providing forensic investigation, expert witness testimony, and litigation support to plaintiff and defense counsel throughout California. Our principal expert, Joe Scerbo, holds active California CSLB licenses in General Building (B #1124663), Electrical (C10 #1124663), HVAC (C20 #1143603), and Alarm Company Qualified Manager (ACQ6091), and has 36+ years of California construction field experience.

We accept engagements from both plaintiff and defense counsel. Our forensic opinions are grounded in site evidence and applicable industry standards — not in the narrative preferred by the retaining party.