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Category Balance and Overlap Auditor

Run the Category Balance and Overlap Auditor MicroSim Fullscreen

About This MicroSim

This is a sample taxonomy: 200 concepts sorted into 12 categories. It has two defects, and they are different kinds of defect — which is the whole point of pairing them in one tool.

Defect one is a balance violation, and the chart shows it to you. Graph Theory & Structure holds 76 of 200 concepts — 38%, well past the 30% ceiling marked by the dashed red line. You can spot this from across the room.

Defect two is a boundary overlap, and the chart is useless for it. Metadata & Standards (8%) and Taxonomy & Classification (7%) are both comfortably balanced. Nothing in their bars looks wrong. But three concepts have a genuine argument for landing in either one:

Concept Argument for Metadata & Standards Argument for Taxonomy & Classification
SKOS It is a published W3C specification Its whole purpose is expressing taxonomies
Concept Label It is a field defined by ISO 11179 Labels are what a taxonomy classifies
Dublin Core Subject Field It is one named field in a standard The subject field is a classification

Balance is a counting problem, and counting is what a chart is for. Overlap is a definitional problem, and no amount of charting will surface it — you have to open the two categories and read their stated boundaries against real concepts. Both are taxonomy defects; neither is caught by Chapter 5's structural validators, which would pass this graph without complaint.

How to Use

  1. Read the chart. Find the category over the 30% ceiling. Click its red bar for an explanation of why concentration is a problem rather than just a number.
  2. Hover any bar for its exact count and percentage.
  3. Click either gold-outlined bar, or the Inspect Overlap button, to open the two flagged categories side by side with their stated boundaries.
  4. Read the three ambiguous concepts and the argument for each category.
  5. Propose a criterion that decides all three, and click Compare with model answer.

On that last step: your criterion is not machine-graded — free text cannot be honestly scored. What the sim does is reveal the model answer and tell you one checkable thing, namely whether your criterion even mentions the axis the model turns on. The real test is the one stated in the prompt: does your criterion place all three concepts, or only two?

Iframe Embed Code

You can add this MicroSim to any web page by adding this to your HTML:

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<iframe src="https://dmccreary.github.io/learning-graphs/sims/category-balance-overlap-auditor/main.html"
        height="562px"
        width="100%"
        scrolling="no"></iframe>

Lesson Plan

Audience

Instructional designers, curriculum developers, and educational technologists working with concept dependency graphs.

Duration

15–20 minutes

Prerequisites

Learners need Category Balance, Category Overlap, and Taxonomy Validation from Chapter 24, plus the 30% balance ceiling introduced in Chapter 4.

Activities

  1. Spot the obvious one (3 min): Learners identify the balance violation from the chart alone and explain why the fix is to split the category rather than move concepts out to make the number look better.
  2. The invisible defect (7 min): Ask the class whether Metadata & Standards and Taxonomy & Classification have any problem, judging from the chart. The honest answer is "no evidence." Then open the overlap panel. Discuss what it means that a chart can give a clean bill of health to a broken taxonomy.
  3. Propose and defend (8 min): Each learner writes a criterion, then tests it aloud against all three concepts. Most first attempts ("is it about classifying?") decide two and split the third. Compare with the model answer and discuss why a criterion that leaves any concept arguable has not resolved the overlap.

Assessment

Learners can:

  • Identify a balance violation from a distribution chart and state the threshold it crosses.
  • Explain why a balanced pair of categories can still be defective.
  • Propose a disambiguating criterion and test it against every ambiguous concept, not just one.
  • Explain why structural validation catches neither defect.
  • Category Balance — the counting property the bar chart measures
  • Category Overlap — the definitional property it cannot
  • Taxonomy Validation — the review this MicroSim simulates
  • Miscellaneous Bucket — the other classic balance smell, not shown here
  • ISO 11179 — the standard behind the Concept Label boundary argument

References

  1. Chapter 24: Taxonomy Design Deep Dive - The chapter this MicroSim supports.
  2. Chapter 4: Concept Taxonomies and Ontologies - Where the 30% category-balance ceiling is introduced.
  3. Taxonomy - General principles of classification, including mutual exclusivity.
  4. Mutually Exclusive and Collectively Exhaustive - The MECE principle, which the overlap defect violates.
  5. Chart.js Documentation - The charting library used to build this MicroSim.