Engineering Ethics and Professional Responsibility

The NSPE Code of Ethics is structured around six fundamental canons. Canon 1 requires engineers to hold paramount the safety, health, and welfare of the public. The remaining canons address competence (performing only within areas of expertise), providing truthful statements in professional matters, acting faithfully for each employer and client, building a professional reputation on service merit, and conducting oneself to uphold the profession's honour.

The ASCE Code of Ethics was revised in 2020. It is organised around four fundamental principles: safety, health, and welfare of the public; sustainability and stewardship of the natural environment; acting with competence and diligence; and acting with integrity, honesty, and justice. The revised code notably elevates sustainability and environmental responsibility in ways the NSPE code does not, which is relevant for forensic engineers involved in environmental or infrastructure failure cases.

Both codes also address competence. The obligation to perform services only within one's area of competence is directly relevant to forensic engineers who are asked, often by litigants who want to minimise expert costs, to opine on matters adjacent to but technically distinct from their primary expertise. An expert who does is not just at risk of producing a bad opinion; they are in breach of their professional code.

The NSPE Code of Ethics §III.2.b requires engineers to promptly notify the proper authority when they observe a violation of applicable engineering codes that endangers public safety, health, or welfare. The ASCE Code makes the same demand. In most forensic contexts, the investigation is historical: the failure has already occurred, the hazard has passed or been isolated. The obligation to report is less acute.

The difficult cases are where the investigation reveals an ongoing hazard. A forensic engineer retained to analyse a failed apartment balcony may find, during the inspection, that every other balcony in the building has the same connection defect. The retaining party may want the investigation kept confidential pending litigation strategy. The professional code does not give the engineer that option.

The tension with attorney-client privilege is real. In the US, a forensic engineer retained at the direction of counsel may be covered by work-product protection, which the attorney can assert to prevent disclosure of the investigation's findings. The work-product doctrine, however, does not override a statutory duty to report. Some jurisdictions have specific statutory requirements, OSHA regulations in the US, for example, impose independent reporting obligations on persons who discover certain categories of workplace hazard, regardless of privilege. The forensic engineer needs to be aware of which category a discovered hazard falls into.

In the United States, the Professional Engineer (PE) licence is issued by each state's engineering licensing board and requires an accredited engineering degree, passing the Fundamentals of Engineering exam, a period of supervised experience (typically four years), and passing the Principles and Practice of Engineering exam. Many states prohibit offering engineering services to the public without a PE licence, and practising without one can be a criminal offence. A forensic engineer who is not PE-licensed in the relevant state can face a qualification challenge.

In the United Kingdom there is no statutory licence to practise as an engineer; anyone can legally call themselves an engineer. The relevant credential is Chartered Engineer (CEng) status awarded by a professional engineering institution (the ICE for civil engineers, the IStructE for structural engineers, the IMechE for mechanical engineers). CEng status requires peer review, continuing professional development records, and a demonstration of engineering competence. It is not mandatory but is treated as a strong qualifier for expert witness work.

For a forensic engineer working across borders, a common situation in major infrastructure or aviation cases, understanding the registration landscape of the jurisdiction in which testimony will be given is essential. An expert who has all the technical credentials may still face a qualification challenge on statutory grounds.

The literature on cognitive bias in forensic contexts has grown substantially since the early 2000s. Two biases appear repeatedly in analyses of forensic engineering failures: confirmation bias and hindsight bias. Both operate unconsciously, both are documented in experimental settings, and both have been linked to specific high-profile engineering investigation errors.

Confirmation bias in failure analysis typically emerges when an expert is given a hypothesis before they examine the evidence. An engineer told by retaining counsel that the failure was caused by a corrosion defect may unconsciously direct their examination toward evidence of corrosion, spend less time on alternative failure modes, and frame ambiguous findings in a way consistent with the corrosion hypothesis. The engineer is not being dishonest; the cognitive system is processing a hypothesis supplied before independent observation began.

Hindsight bias works differently. The forensic engineer reviewing a design failure knows the outcome: the structure failed, people were hurt. That knowledge is almost impossible to fully set aside. Studies by Neal Roese and Kathleen Vohs (2012) and by Chris Guthrie, Jeffrey Rachlinski, and Andrew Wistrich on judicial decision-making both show that people systematically rate outcomes as more predictable after the fact than subjects rating the same situation prospectively do. For an engineer assessing whether a designer met the standard of care, this means a risk of concluding the designer should have foreseen the problem when, evaluated without knowledge of the outcome, a reasonable engineer would not have.

The standard of care question (did the engineer act as a reasonably competent engineer of the time would have acted?) is particularly vulnerable. The forensic engineer must consciously reconstruct the state of knowledge, the applicable codes, and the available information at the time of the design, not assess the design against what they now know after studying the failure. This requires deliberate effort and often benefits from a structured contemporaneous literature and code review rather than relying on memory of what was standard practice.

Both the NSPE and ASCE codes require engineers to be objective and truthful in professional reports and statements. In practice, this means a forensic engineer must be willing to hold and report an opinion that is unfavourable to the retaining party, that contradicts the position of colleagues on the same side, or that reduces their likelihood of future referrals from the law firm.

The referral structure of forensic engineering creates a specific conflict: many forensic engineers receive most of their work from a small number of defence or plaintiff firms. Maintaining independent opinions in that structure requires deliberate attention. Consistent conclusions favourable to a primary referral source warrant examination of whether that pattern reflects genuine technical agreement or gradual drift toward advocacy.

Withdrawal from an engagement is available but not unlimited. An engineer can withdraw when their technical view no longer supports the retaining party's position and the party is seeking to pressure the engineer toward a different conclusion. Withdrawing without explanation can leave the retaining party worse off; the better approach is to provide the honest technical opinion in the report, let the party decide whether to serve it, and withdraw only if asked to change or suppress the opinion rather than simply serve it.

Professional accountability for forensic engineers flows through two channels: professional body discipline and court action (sanctions, adverse cost orders, or evidence exclusion). The two are independent, and a finding in one does not automatically trigger the other, but high-profile failures in both the technical and ethical dimensions of forensic work have led to increased use of both.

In the US, a PE can face licence revocation or suspension by a state licensing board for professional misconduct, including providing fraudulent expert testimony, suppressing material findings, or practising outside competence. Boards investigate complaints; the process is formal and quasi-judicial. The NSPE and state societies maintain ethics consultation services, though formal discipline is conducted by the state boards.

In England and Wales, professional bodies like the ICE and IStructE have disciplinary processes that can strip Chartered status from members found to have violated the codes. Courts have also made adverse findings against expert witnesses whose conduct crossed from independent opinion to advocacy, citing that conduct in judgments that become publicly accessible. The combination of a judgment criticism and a professional body referral can effectively end a forensic engineering practice.

The Forensic Science Regulator in England and Wales does not have a formal remit over forensic engineers (whose work is classed as engineering rather than forensic science under the current framework), but the scientific quality standards the Regulator promotes, ISO/IEC 17020 for inspection bodies, for example, are increasingly cited as best-practice benchmarks in expert witness reports and can be used to challenge methodology during cross-examination when an engineer's process did not follow them.