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Reason Trees

Reason trees are hierarchical structures that organize your reasons into navigable categories. Instead of presenting operators with a flat list of 50+ reasons, a reason tree guides them through 2–3 levels of categories to find the right cause quickly.

How reason trees work​

A reason tree is a parent-child hierarchy where:

  • Branch nodes are categories (e.g., "Mechanical", "Electrical")
  • Leaf nodes are specific reasons (e.g., "Belt broken", "Sensor fault")
  • Each node can have a loss type assignment (or inherit from its parent)
  • Each node can have a color for visual identification

When an operator logs a downtime event, they:

  1. See the top-level categories
  2. Click into the relevant category
  3. Select the specific reason
  4. The loss type is automatically applied from the tree node

Managing reason trees​

Navigate to Admin → OEE → Reason Trees.

Reason trees grid

Creating a Tree​

Click + Create and enter:

FieldRequiredDescription
DescriptionYesName of the tree (e.g., "Packaging Line Reasons")
ActiveYesWhether this tree is available for assignment

Building the Hierarchy​

After creating the tree, open it to access the tree visualizer:

Tree visualizer

Adding nodes​

Click + Add on any node to add a child:

FieldRequiredDescription
ReasonYesSelect from your existing reasons library
Loss TypeNoOEE loss type (inherits from parent if not set)
ColorNoVisual color for dashboards and timelines
CodeNoOptional identifier for integration or reporting

Loss type inheritance​

This is one of the most powerful features of reason trees:

  • Assign a loss type to a branch node (e.g., "Mechanical" → Unplanned)
  • All child nodes automatically inherit that loss type
  • Override at any level when a child needs a different classification

The tree visualizer shows inheritance clearly:

  • Direct assignment: "Loss Type: Unplanned"
  • Inherited: "Loss Type: Unplanned (inherited)"

:::tip Use inheritance to save time For a tree with 50 reasons, you might only need to set loss types on 5–8 top-level categories. Everything underneath inherits automatically. :::

Color coding​

Assign colors to nodes for visual distinction in:

Colors are selected from a predefined palette to ensure consistency.

Duplicating a Tree​

Click Duplicate on any tree to create a copy with all nodes intact. This is useful when:

  • Creating a tree for a similar equipment type with minor differences
  • Testing changes before applying to the production tree
  • Standardizing trees across multiple plants

Import/Export​

Use Export and Import for bulk operations. This supports the full tree structure including hierarchy, loss type assignments, and colors.

Multiple Trees for Different Equipment​

Different equipment types often have different failure modes. You can create separate reason trees for different equipment types:

Equipment TypeReason TreeWhy separate
Packaging LinesPackaging ReasonsJams, seal failures, label issues
Mixing TanksProcess ReasonsTemperature, viscosity, contamination
ConveyorsMechanical ReasonsBelt, motor, alignment

Assign trees to equipment through the Equipment OEE Settings.

Best Practices​

Tree Depth​

  • 2 levels (Category → Reason) works for most plants
  • 3 levels (Category → Subcategory → Reason) for complex operations
  • Avoid 4+ levels: operators won't navigate that deep under time pressure

Node Count per Level​

  • 5–8 top-level categories: scannable at a glance
  • 3–10 reasons per category: manageable selection
  • If a category has 15+ children, split it into subcategories

Review Cycle​

Review your reason trees quarterly:

  • Which reasons are never selected? → Deactivate or merge
  • Which events are classified "Other"? → Add specific reasons
  • Which categories have too many items? → Split into subcategories

Next steps​

  • Analytics — See how reason tree data appears in OEE dashboards
  • Reports — Generate reports by loss type and reason
  • Reasons — Manage the reason library that feeds into trees

Prerequisites​