Statistical learning tools: simple circles explain complex numbers.

• Author: Le Huy Quoc-Benjamin, Nguyen Tang

A professor of international health at the Karolinska Institute in Stockholm, Hans Rosling recognized an ironic situation while teaching young students in Sweden about health problems in rural Africa: while research and statistical data were, expectedly, more easily available to people in rich countries than in poor ones, he felt that those who did not suffer from such hurdles knew much less about their "neighbours" than those who did. "How can we take the numerical data that most countries and the United Nations have compiled and make it available to the public in a more appealing and understandable way?" Dr. Rosling asked. Feeling that it would be easier to understand and remember statistics through visual images, he envisioned a graph that could demonstrate the relationship between health and wealth of countries, symbolized by "bubbles", and their sizes proportional to population. He wanted to enable people to see instinctively where and in what conditions the majority of the world live.

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Rosling's idea was made feasible by one of his students who wrote a computer programme that could plot the statistical data into the graph. The professor was also intrigued by a question most often raised by his students: "How did they [the less developed countries] move up?" He thought that if the bubbles could be made mobile, his graph would better demonstrate the gradual development of each country. One day, his son Ola, then a college student in economic history and art at Gothenburg University, asked him if he could "borrow" and make use of the idea about a visual display that could demonstrate the growth of countries over time. Without hesitation Rosling agreed, and in the fall of 1998 the first prototype came out. He recalled how he, his son and the first viewers were struck by the amount of information they could absorb from these moving "bubbles"--fathoming the twenty-year development progress of the world in twenty seconds.

Having witnessed the impact of a simple prototype on audiences, the Roslings decided to promote this innovative idea and make it of benefit to everyone. They applied for funding from the Swedish Fund for IT (Information Technology) in Learning, but were turned down, and so they decided to use the family's own funds to improve the prototype. In the spring of 1999, an updated prototype plotted a world health chart to visualize international health development and enable better use of health data for learning...