Figure 3. Relative knowledge flows between major geographic areas.

North America and Europe exceed the expected number of citations to all geographic areas by far. South American and Asian papers are less cited than expected. Note that the bars do not measure the distance between competitors, but the rate at which this distance changes. That is, as long as the bar is green, the distance between competitors grows, while the rate at which the distance increases shrinks, if the bar gets shorter. For example, South America has significantly reduced the pace at which the knowledge gap with regard to its competitors increases. Europe and North America are the two most strongly coupled knowledge-producing areas in the world. However, North America has considerably higher relative knowledge flows to South America and Asia than Europe.