Chart Type for Root Cause Analysis. Keywords: root cause, decomposition, tree, hierarchy, drill-down, ai-split, attribution. Best Chart: Decomposition Tree. Secondary Options: Decision Tree, Flow Chart. When to Use: Decomposing a metric into contributing factors; AI-assisted analysis or BI drill-down scenarios. When NOT to Use: No clear parent-child causal relationship; audience expects a summary rather than exploration. Data Volume Threshold: Up to 5 levels deep; limit visible nodes to 20 per level for readability; lazy-load deeper levels. Color Guidance: Positive impact nodes: #2563EB. Negative impact nodes: #EF4444. Neutral connectors: #94A3B8. Accessibility: AA — Keyboard-navigable expand/collapse. Screen reader announces node value and % contribution.. A11y Fallback: Keyboard expand/collapse tree; screen reader announces node label + value + % impact. Library: Power BI (native), React-Flow, Custom D3.js. Interactive Level: Drill + Expand.