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Visualization of Enrollment data using Chord Diagrams - GRAPP 2015

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Conference presentation at GRAPP 2015

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Visualization of Enrollment data using Chord Diagrams - GRAPP 2015

  1. 1. Visualization of Enrollment Data using Chord Diagrams L. Blasco-Soplon, J. Grau-Valldosera, J. Minguillón Universitat Oberta de Catalunya Barcelona, Spain
  2. 2. Context ● UOC: fully online open university – Learners with very diverse backgrounds – No enrollment requirements ● How many subjects? ● Which ones? – Recommendations from ● Subject / course / degree planning (text / table based) ● Mentor ● “Common sense” ● First enrollment is known to be “critical” Visualization of Enrollment Data using Chord Diagrams – GRAPP 2015, Berlin, Germany
  3. 3. Learning Analytics ● Plenty of available data – Since 1994 (EHEA / Bologna degrees since 2008) – Thousands of students each semester ● Hundreds per degree – Tens of thousands of subject combinations – Academic performance ● Subject level (PASS / FAIL) ● Semester level (dropout) ● Can we do it better? Visualization of Enrollment Data using Chord Diagrams – GRAPP 2015, Berlin, Germany
  4. 4. Our proposal ● Analyze subject combinations – 2 x 2 contingency tables (PASS / FAIL) ● Visualize enrollment data – Intra-semester – Inter-semester ● Provide better support (esp. 1st semester) – Learners: adjust enrollment – Mentors: improve recommendations – Degree managers: reduce dropout Visualization of Enrollment Data using Chord Diagrams – GRAPP 2015, Berlin, Germany
  5. 5. Available data (I) ● Paper: Business and Economics degree – From Spring 1999 to Spring 2011 (25 semesters) – 21792 learners – 501 different subjects – 328467 subject enrollments ● New data from EHEA B&E degree (10 sems.) – 5930 learners – 64 different subjects (59 in the 1st semester) – 63460 subject enrollments (17610 in the 1st sem.) Visualization of Enrollment Data using Chord Diagrams – GRAPP 2015, Berlin, Germany
  6. 6. Available data (II) ● First semester only: – High dropout rates – Are learners following institutional advice? ● 5698 learners take 2 or more subjects – 17378 subject enrollments – 59 different subjects ● 13 subjects: 90.6% of learners, 20 subjects: 95.5% – 764 different subject combinations ● 129 combinations: 90.0% of learners Visualization of Enrollment Data using Chord Diagrams – GRAPP 2015, Berlin, Germany
  7. 7. Chord diagrams ● Circular layout for representing relationships in matrix data as a graph – Segments: nodes – Chords: edges ● Position, color, size ● Popularized in 2007 by the NY Times infographic Close-Ups of the Genome by Giovanni Gherdovich Visualization of Enrollment Data using Chord Diagrams – GRAPP 2015, Berlin, Germany
  8. 8. Why chords? ● Explore new ways to provide support ● Subjects can be sorted clockwise – From most to least popular subject (size) – Each subject can be independently colored according to its own PASS / FAIL ratio ● Subject combinations – Popularity + % of learners passing / failing one / two subjects ● Available in D3.js – Interactivity “included” as part of the visualization Visualization of Enrollment Data using Chord Diagrams – GRAPP 2015, Berlin, Germany
  9. 9. Chord parametrization ● Number of segments – Number of chords grows quadratically – Up to 10 segments looks fine, 6-8 seems optimal ● Segment colors – From red (FAIL) to green (PASS) through yellow – Other thresholds can be used: [0, 0.4, 0.6, 1] ● Chord colors – Percentage of learners passing the two subjects – Same red-yellow-green coloring Visualization of Enrollment Data using Chord Diagrams – GRAPP 2015, Berlin, Germany
  10. 10. Interactivity ● By default, show – Subjects ● Size: Importance (number of learners) ● Color: Perfomance (PASS / FAIL ratio) – Chords ● Size: Number of learners taking such combination ● Color: Number of learners passing the two subjects ● Interaction – On a segment: info about that subject and its combinations with other subjects – On a chord: info about that combination Visualization of Enrollment Data using Chord Diagrams – GRAPP 2015, Berlin, Germany
  11. 11. Results demo Visualization of Enrollment Data using Chord Diagrams – GRAPP 2015, Berlin, Germany
  12. 12. Conclusions ● Pros: – Compact visualization, nice aesthetics ● Easy to understand (green: OK, red: KO) – Interactivity reduces data overload – Easy integration into any web based system ● Cons: – 13 subjects generate 13*12/2=78 chords! ● Lack of data for non-common subjects / combinations – Even the simplest visualization needs explanation – What about blind / colorblind learners? Visualization of Enrollment Data using Chord Diagrams – GRAPP 2015, Berlin, Germany
  13. 13. Current and future work ● Evaluate the visualization compared to tables ● Explore other visualization types – Concentric chord diagrams (inter-semester) – D3.js: parallel sets, ... ● Include other parameters – Learners' satisfaction – Total time spent in the subject – Weight as a inter-semester dropout factor ● Integrate it into the UOC enrollment process Visualization of Enrollment Data using Chord Diagrams – GRAPP 2015, Berlin, Germany
  14. 14. Thank you! jminguillona[at]uoc[dot]edu twitter/@jminguillona http://bit.ly/1wcZCBk Visualization of Enrollment Data using Chord Diagrams – GRAPP 2015, Berlin, Germany

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