What is the Hierarchy of Controls?

In Psychological Health and Safety (PHS) the Hierarchy of Controls is a tiered system used to determine the most effective way to mitigate risk. It moves from the most effective (removing the hazard) to the least effective (relying on the individual to cope).

The impact of applying the hierarchy is a shift in responsibility. The hierarchy requires the organization to first attempt to fix the environment itself. This approach reduces the cognitive and emotional burden on the workforce and creates a more sustainable workplace culture.

How the Hierarchy of Controls Relate to the PHS Standard (CSA Z1003 / ISO 45003)

Under the CSA Z1003 and ISO 45003 standards, the hierarchy is adapted specifically for psychological health. It suggests that organizations evaluate controls in the following order of priority:

• Elimination: Removing the psychosocial hazard entirely (e.g., redesigning a role to remove conflicting demands).
• Substitution: Replacing a hazardous process with a less hazardous one (e.g., replacing high-stakes annual reviews with frequent, low-pressure feedback).
• Engineering / Administrative Controls: Implementing policies or technical changes to reduce exposure (e.g., mandatory recovery periods or "no-meeting" blocks).
• Individual/Personal Protection: Providing tools for individuals to manage stressors that cannot be removed (e.g., EAP programs, resilience training, or stress management workshops).

Why the Hierarchy of Controls Matters for Leaders & HR

The aforementioned hierarchy is a strategic resource allocation tool. Without it, organizations often spend significant budgets on "bottom-tier" solutions while the Root Cause Analysis of stress remains unaddressed.

Higher-tier controls (Elimination/Substitution) are more effective and require less maintenance than lower-tier controls, which require constant employee participation. In the event of a claim, an organization that can demonstrate they attempted to "eliminate" a hazard before moving to "coping strategies" has a much stronger Reasonable Care defense.

How to Address the Hierarchy of Controls in Your Organization

To implement the hierarchy effectively, it should be embedded into the PHS-IMS as the primary decision-making filter for risk mitigation. Use the hierarchy to align HR policies with operational workflows. If an Administrative Control (like a communication policy) is failing, the system should trigger a review to see if a higher-tier Substitution or Elimination is possible.

When a psychosocial hazard is identified—such as chronic overtime—the first question should be, "Can we eliminate the need for this work?" rather than "How can we help employees manage the stress of overtime?" Use data to determine which tier of the hierarchy is required. If pulse surveys consistently show high levels of role ambiguity, an Administrative Control like "Job Description Review" is the appropriate hierarchical response.

Record the rationale for why a specific tier was chosen. If Elimination was not possible, document the operational reasons why, then move to the next level. This provides the necessary evidence of Due Diligence.

Hierarchy of Controls in Psychological Health and Safety

Most organizations spend a significant PHS budget on the bottom tier of the hierarchy (Individual Coping). The goal is to design a workplace where employees don't need to be super-resilient just to survive their Monday morning by integrating a PHS Management System into your daily operations.

While many organizations implement mental health initiatives, most inadvertently settle for the least effective methods. A critical "worker-focus" bias often occurs where the burden of safety is placed on the individual rather than the system. To bridge the gap, leaders can apply the PHS Hierarchy of Controls through five diagnostic questions.

The 5-Question Diagnostic for PHS Controls