Retelling the PISA story

The Programme for International Student Assessment (PISA) survey has been running every 3 years since 2000, assessing 15 year old students worldwide.

My task was to find a story within the data and visualise it. The 2012 Performance Snapshot struck me as wildly inaccessible. Why?

2012 Performance Snapshot

*Low font size figures
*Confusing overworded labels
* No performance figures for reading and science
*No geographical context
*No summary of the test itself
*Colour and bold not used well
*Not immediately obvious how the countries are sorted

My mission, to do better.

The Data

First step, download the data and create the features I’m interested in:

  • country
  • for each subject (maths, reading, science)
    * ranking
    * mean score
    * low achievement (% below level 2)
    * low achiever? (below OECD average)
    * top performance (% level 5 or 6)
    * top performer? (above OECD average)
    * progress? (annualised change based on data from previous years)

The Story

A different story for every reader with the narrative in two parts:

1. Animation: showing scores, performance and progress worldwide.
2. Interaction: handing the reins to the user with the ability to:
* look again at the animation maps
* view more detailed statistics for individual countries

The Visualisation

I had two key objectives:

* Tell the story well — always the most important part.
* Be pre-processing friendly
 — readable fonts, clear labels, map for geographical context, clear colour-coding.

My Story

There are 9 consistent high performers: China, South Korea, Japan, Singapore,Australia, New Zealand, Finland, Canada and Leichtenstein.

Six of whom are in the top 10: China, South Korea, Japan, Singapore, Finland and Leichtenstein.

The UK is around average on all subjects but this is only 3% off low achievement.Why are we doing so badly, particularly against our peers in Europe?

Over to you

I hope you enjoy the final visualisation.

D3 areas covered: d3.geo.mercator() projection, colour scales, gradient scales, setInterval animations, responsive option boxes, text elements, interaction with HTML.

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