What-if Analysis: Proactively Identifying Risks in Projects

Every project-whether it’s a new chemical processing plant, a construction site near a wetland, or a waste treatment facility-carries risks. Some of those risks are obvious, but many are hidden beneath layers of assumptions and routine. What-if analysis is one of the most straightforward yet effective risk assessment methods available. It uses structured brainstorming to ask a simple but powerful question: “What if something goes wrong?” The answers to those questions can prevent accidents, protect the environment, and save lives.

What is what-if analysis? 🔗

At its core, what-if analysis is a team-based, qualitative risk assessment method that relies on brainstorming to uncover potential hazards in a system, process, or project. A group of experienced people gathers together, walks through a process step by step, and asks “what if” questions at each stage. What if a valve fails? What if a chemical spills during transfer? What if power is lost during a critical operation?

The technique doesn’t require complex mathematical models or specialized software. It draws on the collective knowledge and experience of the team to identify scenarios that could lead to harmful outcomes. Once those scenarios are identified, the team evaluates the likelihood and severity of each one and recommends appropriate corrective actions.

What-if analysis is recognized by OSHA as an acceptable method for conducting process hazard analysis, particularly for facilities handling hazardous chemicals. It is widely used in chemical processing, manufacturing, oil and gas, construction, and environmental management.

Key steps in the what-if analysis process 🔗

While what-if analysis is less rigid than methods like HAZOP (Hazard and Operability Study), it still follows a clear sequence of steps. Here’s how the process typically works.

Step 1: Define the scope and boundaries 🔗

Before any brainstorming begins, the team must decide what exactly is being analyzed. This could be a single piece of equipment, a particular phase of a project, or an entire facility. A narrowly defined scope tends to produce more detailed and actionable findings. A broad scope, on the other hand, generates higher-level insights. As MIT’s hazard analysis guide notes, clearly defining the boundaries of the analysis is essential for starting the review effectively.

Step 2: Assemble a multidisciplinary team 🔗

The quality of a what-if analysis depends heavily on the people involved. The team should include individuals with diverse expertise-operations staff, engineers, maintenance personnel, safety specialists, and anyone else who has direct knowledge of the process being reviewed. Frontline workers with hands-on experience are especially valuable because they often know about failure modes and risks that don’t appear in design documents.

An experienced facilitator is essential. This person leads the discussion, ensures all team members contribute, and keeps the session productive and focused. A scribe or recorder is also assigned to document all findings, judgments, and follow-up actions in real time.

Step 3: Gather background information 🔗

Before the review session, team members should have access to relevant documentation. This includes process flow diagrams, piping and instrumentation diagrams (P&IDs), operating procedures, maintenance records, and any past incident reports. Walking through the actual facility or process area beforehand-sometimes called a field walkdown-also helps team members understand the physical layout and spot potential issues that may not appear on paper.

Step 4: Generate what-if questions 🔗

This is the heart of the analysis. Using the documentation and their own experience, team members systematically pose hypothetical questions about what could go wrong. These questions typically cover areas such as:

Human errors – What if an operator fails to follow the correct procedure? What if the wrong chemical is added?
Equipment failures – What if a pump stops working? What if a safety valve doesn’t open?
Process upsets – What if temperature exceeds the design limit? What if pressure fluctuates unexpectedly?
External events – What if there’s a power outage? What if an earthquake occurs?
Utility failures – What if cooling water supply is interrupted? What if ventilation stops?

The facilitator encourages the team to be thorough and creative, ensuring that no category of risk is overlooked. It’s important that the team generates all questions first before moving on to evaluating them-this prevents premature closure on ideas.

Step 5: Answer the questions 🔗

Once a comprehensive list of what-if scenarios has been compiled, the team works through each one. For every question, they determine: What would actually happen if this scenario occurred? What are the consequences for people, equipment, and the environment? For example, if the question is “What if a chemical drum is mislabelled?” the answer might involve an incompatible material being added to a reactor, leading to a dangerous exothermic reaction.

Evaluating risk and generating solutions 🔗

After the team has identified potential scenarios and their consequences, the next step is to assess the level of risk each one presents and decide what to do about it.

Assessing likelihood and consequence 🔗

For each what-if scenario, the team evaluates two key factors: how likely the event is to occur, and how severe the consequences would be if it did. Many organizations use a risk prioritization matrix for this purpose. This tool plots likelihood against consequence to produce a risk rating-typically ranging from low to extreme. Consequence is generally assessed without assuming that safety barriers work perfectly, while likelihood considers whether effective protective measures are already in place.

Ranking and prioritizing risks 🔗

Not all risks demand the same response. Using the matrix, the team ranks each scenario by its overall risk level. High-priority items-those with high likelihood and severe consequences-are flagged for immediate corrective action. Moderate risks may call for additional safeguards or monitoring. For low-probability, low-consequence risks where corrective measures would be costly and time-consuming, the team may document the risk and note that no immediate recommendation is needed.

Developing recommendations 🔗

For each risk deemed unacceptable, the team develops a specific recommendation. This could include engineering controls (installing a pressure relief valve), administrative controls (updating a standard operating procedure), additional training, or changes in the process design itself. Each recommendation should have a clear responsible person or team assigned to it, along with a defined timeline for completion.

The analysis is then compiled into a report. This report typically includes all the what-if questions, the identified consequences, risk rankings, and the recommended corrective actions. In many organizations, a periodic follow-up cycle-often every three to five years-ensures that the analysis remains current and that all recommendations have been addressed.

Where what-if analysis is applied 🔗

What-if analysis is versatile. It can be used at virtually any stage of a project’s lifecycle-during the conceptual design phase, before commissioning, during operations, or even during decommissioning. It is particularly effective in the early stages of process design or modification, when detailed engineering data may not yet be available and more formal methods like HAZOP are not yet practical.

In the context of environmental impact assessment (EIA), what-if analysis helps identify risks to ecosystems, water bodies, air quality, and nearby communities. For instance, before constructing an industrial facility near a river, a what-if analysis might explore scenarios like: What if a containment wall fails during heavy rain? What if hazardous waste leaks into the groundwater? These questions help environmental teams develop preventive and emergency response measures well ahead of time.

The method is also commonly applied in oil and gas operations, pharmaceutical manufacturing, food processing, and any other setting where process failures could have serious safety or environmental consequences.

Benefits of what-if analysis 🔗

What-if analysis offers several distinct advantages that make it one of the most widely used hazard identification tools.

Simplicity and accessibility. Unlike highly technical methods such as Fault Tree Analysis or Quantitative Risk Assessment, what-if analysis does not require specialized training or software. People with operational experience can participate fully and meaningfully, even without a background in formal risk analysis techniques.

Flexibility. The method adapts to virtually any type of process, system, or facility. It works for simple packaging operations, complex chemical plants, laboratory experiments, and large-scale environmental projects alike.

Speed. A what-if analysis can be completed relatively quickly, and its results are available immediately. This makes it especially useful when quick safety assessments are needed-for instance, before introducing a change to an existing process.

Encourages team collaboration. Because it is fundamentally a brainstorming exercise, what-if analysis promotes team communication and draws on diverse perspectives. This collaborative approach often uncovers risks that no single individual would identify on their own.

Applicable at any stage. Whether a project is still in the design phase, already operational, or undergoing maintenance, what-if analysis remains a useful tool for evaluating risks.

Limitations of what-if analysis 🔗

Despite its strengths, what-if analysis has notable limitations that teams should keep in mind.

Highly dependent on team quality. The technique relies on the experience, knowledge, and creativity of its participants. If the team lacks expertise in the specific process or if key disciplines are not represented, important hazards may be missed entirely. As process safety experts have noted, the subjective nature of the method can lead to biases or the overlooking of certain hazards.

Quality of questions matters. The entire analysis is only as good as the questions posed. Poorly framed questions, or a failure to consider certain categories of risk (like external events or cascading failures), can leave significant gaps in the analysis.

No quantitative output. What-if analysis is qualitative. It does not produce numerical risk estimates the way methods like Fault Tree Analysis or Quantitative Risk Assessment do. For complex, high-consequence systems where precise probability data is needed to inform decisions, what-if analysis alone may not be sufficient.

Less systematic than alternatives. Compared to structured methods like HAZOP, which use guide words and systematically examine each process node for deviations, what-if analysis is more free-form. This flexibility is an advantage in some contexts but can also mean that the analysis is less consistent or less thorough than a more formal approach.

Documentation can be inconsistent. Without a disciplined facilitator and scribe, important findings may not be captured properly. The informal nature of the method can sometimes lead to incomplete records.

What-if analysis versus other risk assessment methods 🔗

It helps to understand where what-if analysis fits relative to other common techniques. HAZOP is more structured and systematic-ideal for complex systems but more resource-intensive. Fault Tree Analysis (FTA) provides a quantitative, top-down analysis of failure causes but requires detailed failure data. Bowtie analysis visually maps causes and consequences of hazardous events, making risk communication clearer.

What-if analysis is often used as a starting point. It works well for initial hazard screening and brainstorming, and its findings can inform whether more detailed analyses like HAZOP or FTA are needed for specific high-risk areas. In many organizations, what-if analysis and checklists are combined into a hybrid “what-if/checklist” approach that brings the creativity of brainstorming together with the thoroughness of a predefined checklist.

Making the most of what-if analysis 🔗

To get the best results from a what-if analysis, a few practical guidelines are worth following. First, invest time in assembling the right team-diverse experience is the single biggest factor in the quality of the outcome. Second, prepare thoroughly. Ensure all relevant documentation is available and that team members have had a chance to review it before the session. Third, use a skilled facilitator who can keep discussions focused, draw out quieter team members, and prevent the group from jumping to conclusions too quickly.

Finally, treat the analysis as the beginning of a process, not the end. The real value of what-if analysis comes from following through on its recommendations-assigning responsibility, setting deadlines, and verifying that corrective actions are implemented.

What do you think? Have you seen what-if analysis used effectively in your workplace or academic projects? In your experience, what makes the difference between a productive brainstorming session and one that misses critical risks?

References

1. https://onlinelibrary.wiley.com/doi/abs/10.1002/9781119798323.ch7
2. https://safetyculture.com/topics/risk-assessment/process-hazard-analysis
3. http://web.mit.edu/course/10/10.27/www/1027CourseManual/1027CourseManual-AppVI.html
4. https://www.onshoresafetyalliance.org/-/media/BrightfindOSA/Resource-Library/What-If%20Methodology.pdf
5. https://cdms.com/what-is-a-process-hazard-analysis/
6. https://stonehousesafety.com/which-risk-assessment-technique-for-me/
7. https://sigma-hse.us/blog/process-hazard-analysis-methodologies/
8. https://saltegra.com/process-hazard-analysis/what-if-checklist-analysis