Learning Graph Quality Metrics Report

Overview

• Total Concepts: 337
• Foundational Concepts (no prerequisites, other concepts depend on them): 3
• Terminal Nodes (nothing depends on them, but have prerequisites): 128
• Orphaned Nodes (completely disconnected, no edges): 0
• Concepts with Dependencies: 334
• Average Dependencies per Concept: 1.61

Graph Structure Validation

• Valid DAG Structure: ✅ Yes
• Self-Dependencies: None detected ✅
• Cycles Detected: 0

Foundational Concepts

These concepts have no prerequisites:

• 1: Digestive Tract
• 4: Central Nervous System
• 43: Microorganism

Dependency Chain Analysis

• Maximum Dependency Chain Length: 23

Longest Learning Path:

1. Central Nervous System (ID: 4)
2. Peripheral Nervous System (ID: 5)
3. Autonomic Nervous System (ID: 6)
4. Parasympathetic Nervous System (ID: 26)
5. Vagus Nerve (ID: 27)
6. Afferent Signal (ID: 28)
7. Nucleus Tractus Solitarius (ID: 31)
8. Interoception (ID: 34)
9. Insula (ID: 136)
10. Pain Perception (ID: 138)
11. Visceral Hypersensitivity (ID: 140)
12. Gut-Brain Interaction Disorder (ID: 166)
13. Irritable Bowel Syndrome (ID: 168)
14. Placebo Response (ID: 181)
15. Open-Label Trial (ID: 224)
16. Placebo-Controlled Trial (ID: 225)
17. Randomized Controlled Trial (ID: 253)
18. Hierarchy of Evidence (ID: 324)
19. Peer Review (ID: 326)
20. Reading an Abstract (ID: 334)
21. Claim-Checking Method (ID: 335)
22. Science Communication (ID: 336)
23. Student Research Project (ID: 337)

Terminal Nodes Analysis

Terminal nodes are concepts that nothing else depends on but have prerequisites. They represent natural endpoints of learning paths: culminating or specialized concepts.

• Total Terminal Nodes: 128 (38.0% of all concepts)
• Healthy Range: 5-40% of total concepts

Concepts at the end of learning paths:

• 10: Submucosal Plexus
• 12: Enteric Glia
• 16: Migrating Motor Complex
• 19: Hirschsprung Disease
• 20: Second Brain Metaphor
• 36: Neuropod Cell
• 40: Satiety Signal
• 51: Bacteria-to-Human Cell Ratio
• 53: Birth Mode and Microbes
• 58: Metagenomic Sequencing
• 62: Defining a Healthy Microbiome
• 72: Interleukin-6
• 77: Circumventricular Organ
• 80: Sickness Behavior
• 85: Tryptophan Hydroxylase
• 88: SSRI
• 90: Gut Serotonin Mood Myth
• 93: Acetylcholine
• 94: Microbe-Made Neurotransmitter
• 95: Kynurenine Pathway

...and 108 more

Orphaned Nodes Analysis

Orphaned nodes are completely disconnected concepts with no inbound AND no outbound edges. These indicate a quality problem, since every concept should connect to the graph.

• Total Orphaned Nodes: 0

✅ No orphaned nodes detected. All concepts are connected to the graph.

Connected Components

• Number of Connected Components: 1

✅ All concepts are connected in a single graph.

Indegree Analysis

Top 10 concepts that are prerequisites for the most other concepts:

Rank	Concept ID	Concept Label	Indegree
1	4	Central Nervous System	11
2	44	Gut Microbiota	10
3	71	Cytokine	10
4	147	Inflammatory Bowel Disease	10
5	168	Irritable Bowel Syndrome	9
6	183	Major Depressive Disorder	8
7	198	Celiac Disease	8
8	260	Probiotic	8
9	46	Bacterial Strain	7
10	61	Correlation vs Causation	7

Outdegree Distribution

Dependencies	Number of Concepts
0	3
1	150
2	164
3	20

Recommendations

• ✅ Terminal node percentage (38.0%): Within healthy range (5-40%)
• ✅ DAG structure verified: Graph supports valid learning progressions
• ℹ️ Long dependency chains (23): Ensure students can follow extended learning paths

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Report generated by learning-graph-reports/analyze_graph.py