Human Factors in Risk Analysis
Let’s be honest, when was the last time you actually read the manual of a product before using it? Exactly. You’re not alone. Most people don’t read the manual when assembling flat-pack furniture.
The same goes for configuring a router or setting up a kitchen appliance. They usually skim it only when things go wrong. This behavior isn’t limited to consumers. Technicians, operators, and even engineers cut corners when instructions get too long. Instructions also are often unclear or inconvenient.
Yet, despite this well-known human habit, product safety files, risk assessments, and certification strategies continue to depend on instructions. They also rely on warning labels. They act as if these are bulletproof safety nets.
Often, the manual dedicates a large portion to describing risks and potential effects of misuses. This turns a guide for the user into a disclaimer. They’re not. If your product depends on users reading the manual to stay safe, you’re designing for a world that doesn’t exist.
In the field of compliance, this is more than just a bad assumption. It’s a dangerous shortcut. It may be valid in court but does not really prevent injuries. And it’s one of the key reasons why products pass lab tests but still fail in real life.
When Documentation Defeats Safety
The phenomenon of the “clogged manual” is a direct symptom of a defensive engineering culture. When we sit down to draft technical documentation, the legal department often has as much influence as the safety engineers.
This results in a document that is optimized for a courtroom rather than a workshop or a living room. We clearly see this in the “Safety Summary” sections. These sections have ballooned from a single page of essential precautions. They have grown to ten-page dossiers of generalized warnings. By trying to protect the company from all possible liability claims, no matter how unlikely, we unintentionally create a new risk. This risk is the total erosion of the user’s trust and attention.
The core of the issue lies in the dilution of signal by noise. In information theory, the more redundant or irrelevant data you add to a channel, the harder it is for the receiver to extract the meaningful message. When a user sees a “WARNING” symbol attached to a common-sense instruction like “do not submerge the power cord in water,” the symbol loses its psychological impact. By the time they reach a truly unique and critical hazard, they encounter a specific sequence required to safely discharge a high-voltage capacitor. By that point, their brain has already categorized the triangular warning icon as “ignorable background noise.”
Manuals are not for regulatory professionals
We must recognize that a manual can be technically compliant with every global marking directive. However, it still fail from a safety perspective if it isn’t usable. If the goal is to bridge the gap between standards and reality, we have to advocate for a “lean” approach to documentation. This involves separating the legal “CYA” (Cover Your Assets) content from the instructional content. You can move the dense warnings to a dedicated section at the back.
Ultimately, the producer’s primary legal defense shouldn’t be “we told them not to do it on page 42”; it should be “we designed the product so they didn’t need a manual to stay safe“.
We need to stop using the manual as a dumping ground for liability concerns. Then, we can return to its original purpose: a clear, concise guide for the safe and efficient use of technology. We need to challenge the assumption that more warnings equal more safety; in reality, the opposite is often true because a clogged manual is a manual that stays in the box.
Warnings Are Residual Controls – Not Primary Safety Measures
If your safety strategy relies on a human being reading, understanding, and perfectly remembering a set of instructions, you aren’t designing for safety, you’re designing for a fantasy. In regulatory circles, this over-reliance on documentation is a common pitfall. It can lead to catastrophic field failures. This can happen even if the product technically passes laboratory tests. We need to shift our mindset from blaming the user for “failing to follow instructions” to acknowledging that the instruction manual is often the weakest link in the safety chain.
According to international standards like ISO 12100 (Safety of Machinery – General Principles for Design) and IEC 62368-1 (Audio/video, information and communication technology equipment), risk reduction follows a clear hierarchy
- Eliminate hazards by design
- Apply safeguarding and protective devices
- Warn users as a last resort
This is called the Three-Step Method. Warnings, labels, and instructions sit firmly at the bottom of that hierarchy.
The inversion of the correct process
When we look at modern risk assessments, we often see a dangerous inversion of this hierarchy where “refer to manual” becomes the primary mitigation for complex hazards.
The following list highlights the core reasons why relying on the user manual as a primary safety control is a flawed approach for any compliance professional:
- Selective Attention: Users typically skim manuals looking for specific setup steps, completely bypassing the “Safety Information” section.
- Cognitive Load: If a product requires a 50-page manual to operate safely, the sheer volume of information ensures that critical safety details will be forgotten.
- Environmental Context: In industrial settings, manuals are often lost, damaged, or stored in an office far away from the actual machine being operated.
- Language and Literacy: Even with professional translations, technical jargon can be misinterpreted or lost on users who lack specialized training.
Manuals nowadays are a static tool being used in a dynamic, often chaotic environment. If a user is tired, under pressure to meet a deadline, or simply overconfident, the “warning” on page 4 becomes invisible. This is why we must treat instructions as a secondary support system rather than a shield against liability.
“Read the Manual”: A Lazy Risk Mitigation
When we see the phrase “refer to manual” peppered across the risk analysis, it raises a red flag. This occurs in the FMEA as a mitigation for electrical hazard, misuse, or maintenance error
Not only is this approach incredibly vague, but it is also demonstrably ineffective in the field. It serves as a placeholder, only to closes a cell in a spreadsheet. It is not a genuine engineering solution to a known hazard.
The industry’s over-reliance on this “paper shield” is rarely the result of a conscious choice to be unsafe. Instead, it is usually a byproduct of systemic pressures within the product development lifecycle that force safety to take a backseat to speed. We often see this lazy mitigation surfacing due to the following critical failures in the design process:
- Time pressure during development
- Uncertainty about residual risks
- Desire to avoid difficult design changes
Slapping a warning on a product to cover poor design is not compliance. It addresses known weak points but becomes a liability. This is the last resort and should be used only when residual risk is reduced and can be considered low. Relying solely on the manual or a label for safety is insufficient. You have not taken all necessary steps to prevent injuries.
And let’s be honest. Only a small portion of the manuals we see are well thought out and documented. They are easy to read and understand.
To rely on such kind of instruction will inevitably cause misunderstanding and misuses.
Misuse Due to Ignored Instructions Is Still Foreseeable
Another major misconception is that if the user ignores the manual, it’s “on them.” Not so fast. Reasonably foreseeable misuse is an explicit requirement in many risk-based standards, including IEC 61010 and ISO 14971.
In the eyes of regulators, if a user ignores a warning and gets hurt, the manufacturer is often still held responsible if that misuse was “reasonably foreseeable.” Foreseeable misuse isn’t just a legal term; it’s a design reality that recognizes humans will always try to find the path of least resistance.
If a cable can be plugged into the wrong port, someone will eventually do it. If a safety guard can be bypassed to make a job faster, an operator will likely try. Designing for compliance means anticipating these behaviors. It involves using physical barriers, like keyed connectors or non-resettable thermal cutouts, to make the “wrong” way impossible, and avoid burn injuries. We must stop viewing misuse as a failure of the user and start seeing it as a failure of the design to guide the user safely.
Foreseeable misuse includes:
- Skipping grounding steps
- Overloading power outlets
- Incorrect assembly of moving parts
- Leaving a product in direct sunlight or near heat sources
If you’ve seen it happen during customer support, in field service, or during testing, it’s foreseeable.
And we need to handle it not with a note in the manual. We should use design or physical barriers where possible.
Real-World Feedback: The Best Manual You’ll Ever Read
The Myth of the “Perfect” Manual
Let’s be honest about the state of technical documentation today. Only a microscopic portion of the manuals we encounter in the lab are well-thought-out, and actually useful to users. Most are a chaotic jumble of poorly translated warnings, grainy diagrams, and font sizes that require a magnifying glass. To rely on this caliber of instruction for life-critical safety is to invite disaster. When the documentation is a chore to read, it will inevitably cause the very misunderstandings and misuses it was supposedly designed to prevent.
Furthermore, we must address the “False Sense of Security” that these documents provide to the manufacturer. A producer might feel legally protected because they mentioned a specific hazard on page 84, but from a technical quality perspective, that protection is an illusion. If the manual is the only thing standing between a user and a 230V shock, you haven’t built a safe product; you’ve built a trap with a disclaimer attached to it.
Real-World Feedback
The most effective “manual” ever written is the one created by your customers through their real-world behavior. By analyzing product returns, support tickets, and field reports, we can see exactly where the manual is failing to bridge the gap between design and reality. If you notice a recurring pattern of “accidental” damage, take it as a signal. A design change is required when you see recurring safety-related questions.
Important aspects to consider when drafting manuals are:
- Product returns
- Customer complaints
- Support tickets
- Field technician reports
If users are misusing the product in a consistent way, the fix isn’t better wording, it’s better design. Maybe a connector needs to be keyed. Maybe a handle needs better labeling. Or an operation mode should be impossible under certain conditions.
Each of these changes physically removes the possibility of misuse, making the manual irrelevant for that task.
In a time where the product gets even more complicated every day, this goal is more challenging. Nevertheless, it still remains the objective. An effective product should be used safely without the need of memorizing a manual.
Expanding the Scope: The Psychology of Compliance
To truly master human factors, we have to look beyond the physical interaction and into the psychology of the user. Most users operate on “mental models”, preconceived notions of how a product should work based on their experience with similar devices. If your product deviates from these universal expectations, you need to do more than explain the difference in the manual. This sets the stage for an accident. For instance, if every other power tool in a specific industry uses a red button for “stop,” but your design uses it for “turbo mode,” no amount of bold text in a manual will prevent a user from hitting that button in an emergency.
Furthermore, we must account for the “Normalization of Deviance.” This happens when a user takes a shortcut once, nothing bad happens, and so the shortcut becomes the new standard operating procedure. Over time, the safety instructions in the manual become perceived as “lawyer-talk” rather than vital guidance. As safety technicians, our job is to ensure that the physical product provides constant, intuitive feedback that reinforces safe behavior without needing a paper reference.
Internal Tools & Articles You Can Use
To address this practically, you start with these internal resources:
- 🧩 Creating Effective FMEA – Revise your FMEAs to downgrade manual references and prioritize real design mitigations.
- 🧠 Risk Perception in Compliance Documentation – See how bias affects documentation. Learn how teams can align closer to user reality.
Do not use your FMEA as a documentation formality. Instead, use it as a critical thinking tool. Would this control still work if the user didn’t read anything? If the answer is no, it’s time to rework it.
Make Instructions Your Safety Backup, Not Your Safety Plan
Instructions and labels should only reinforce what’s already designed to be safe. They’re supporting actors, not lead roles.
Next time you evaluate a risk, ask yourself:
“If a toddler, a tired worker, or someone with zero tech skills used this—would they stay safe without the manual?”
If not, the manual isn’t your safety strategy. It’s a fallback.
The Shift Toward Active Mitigation
To move away from “lazy” risk mitigation, technicians and engineers must challenge the FMEA every time “refer to manual” appears. We should be asking: “Why can’t this be solved with a physical barrier?” or “Can we use a software limit to make this misuse impossible?” True safety is quiet and invisible; it doesn’t require the user to be a scholar of your documentation. It exists in the hardware, the firmware, and the mechanical assembly.
By prioritizing active mitigations over passive instructions, we create products that are resilient to human error. This transition doesn’t just make for a smoother certification process with the Notified Body; it builds a brand reputation for quality and reliability. In the end, a product that doesn’t need a manual to be safe is a product that truly respects the user.
Misuse is normal
In Part 2 of this series, we’ll explore why “Misuse Is Normal, Not Exceptional”. We will also discuss how documenting it correctly can prevent compliance failures. This approach can also help avoid lawsuits.
