---
title: "The Risk Assessment Matrix"
url: "https://docs.4hse.com/guides/work-phases-and-risk-assessment/risk-evaluation-matrix"
description: "Guide to using the PxD matrix for risk assessment within work phases in 4HSE."
---

# The Risk Assessment Matrix

Risk **assessment** in 4HSE can be performed using the **PxD matrix**, accessible from the **Work Phases** menu via the button within each risk entry.

![risk evaluation button](/_astro/risk-evaluation-matrix-1.CSPVWoum_Z1xQwJY.webp)

The matrix allows you to define **Probability** and **Damage** values to determine the **Initial Risk**. After linking **mitigation actions**, each can be assigned an impact value on the **initial risk**, which may be adjusted over time. This results in the **Residual Risk** value.

![risk evaluation matrix](/_astro/risk-evaluation-matrix-2.OqljpyO2_Zic2qO.webp)

## Probability and Damage: Matrix Structure

[Section titled “Probability and Damage: Matrix Structure”](#probability-and-damage-matrix-structure)

The **matrix** is structured as a Cartesian grid, with:

-   the **Damage (D)** value on the X-axis, representing the impact severity if the event occurs
-   the **Probability (P)** value on the Y-axis, representing how likely the event is to occur

Each risk has both an **initial value** and a **final (residual) value**. The final value depends on the **mitigation actions** taken, for which you can define their **impact** on both probability and damage.

**Probability** and **Damage** are rated on a scale from 1 to 9:

-   From **Unlikely** to **Very Likely** for probability
-   From **Minor** to **Very Severe** for damage

![definition of probability](/_astro/risk-evaluation-matrix-3.DVOFQ7Zo_Z1NN9TI.webp)

![definition of damage](/_astro/risk-evaluation-matrix-4.DWqHbkpV_1EICSG.webp)

To **add** a mitigation action (after it has been linked to the relevant work phase):

1.  Click the **Actions** tab at the bottom
2.  Click **New** and select the desired action
3.  Define the **impact values** for probability and damage
4.  Click **Save** to confirm the entry or changes

![setting the impact of an action on a risk](/_astro/risk-evaluation-matrix-5.B6Sf6REe_wegmQ.webp)

## Risk Values

[Section titled “Risk Values”](#risk-values)

After defining **probability**, **damage**, and linking the necessary **actions**, the matrix will display two risk values:

-   **Initial Risk**
-   **Residual Risk**

Each risk value is represented by a **color** indicating the **severity** and corresponding **priority for action**:

-   **Blue**: very low
-   **Green**: low
-   **Yellow**: medium
-   **Orange**: high
-   **Red**: very high

You can view the full legend, including the associated risk values and intervention priorities, by hovering over the **question mark icon** next to **Risk Matrix**.

![definition of risk values](/_astro/risk-evaluation-matrix-6.CsyXN-WU_Z1p520R.webp)

The list of risks associated with each work phase is shown in the **Risks** tab (where you previously accessed the assessment matrix), displaying:

-   **Initial Risk**
-   **Variation**
-   **Final Risk**

To **edit the values**, either double-click the corresponding row or click the **open in new window** button.

![display of the final risk](/_astro/risk-evaluation-matrix-7.DEVQMBi9_Z2itazQ.webp)

**Note:** If a risk has been entered but not yet assessed, all three values will be 0.

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