Article type
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Abstract
Background: Brain drain, the international migration of scientists in search of better opportunities, has been a long-standing concern and represents a major gap in the ability to share scientific progress across the globe. Nevertheless, quantitative measurements of this phenomenon are uncommon and limited to specific countries or disciplines. We need to understand brain drain at a global level and estimate also the extent to which scientists born in countries with low opportunities never materialize their potential. Objective: The objective was to assess the extent of brain drain and brain deficit across the globe for various disciplines and countries.
Methods: Data were analyzed on 1523 of the most highly cited scientists for 1981-1999 based on the Institute for Scientific Information databases and additional information retrieved through web searches on their place of birth and residence. Population-adjusted modelling was used to estimate the ratio of actual over expected top scientists in each country of the globe using the USA population as reference.
Results: Overall, 31.9% of the scientists in the analysed sample did not reside in the country where they were born. The range was 18-55% across 21 different scientific fields. The lowest rates were seen in general social sciences (18%), immunology (19%), and clinical medicine (21%). There was large variability across developed countries in the proportions of foreign-born resident scientists and emigrating scientists (p<0.001 for both). Among countries without sufficient critical mass of locally born scientists, the emigration rate was very high even in countries with established market economies (77% [95% CI, 65-87%]) and reached 93% (95% CI, 85-97%) in other countries. Women accounted for only 3% of the sample.
Adjusting for population and using the USA as reference, the number of highly cited scientists born was at least 75% of the expected number in only 8 other countries. It was estimated that approximately 94% of the expected top scientists worldwide have not been able to materialize themselves due to various adverse conditions.
Conclusions: Countries without a critical mass of native scientists lose most scientists to migration. This loss occurs in both developed and developing countries. The vast majority of the scientific potential worldwide has been stifled by various adverse conditions. Scientific deficit is only likely to help perpetuate these adverse conditions and widen the gap between rich and poor countries.
Methods: Data were analyzed on 1523 of the most highly cited scientists for 1981-1999 based on the Institute for Scientific Information databases and additional information retrieved through web searches on their place of birth and residence. Population-adjusted modelling was used to estimate the ratio of actual over expected top scientists in each country of the globe using the USA population as reference.
Results: Overall, 31.9% of the scientists in the analysed sample did not reside in the country where they were born. The range was 18-55% across 21 different scientific fields. The lowest rates were seen in general social sciences (18%), immunology (19%), and clinical medicine (21%). There was large variability across developed countries in the proportions of foreign-born resident scientists and emigrating scientists (p<0.001 for both). Among countries without sufficient critical mass of locally born scientists, the emigration rate was very high even in countries with established market economies (77% [95% CI, 65-87%]) and reached 93% (95% CI, 85-97%) in other countries. Women accounted for only 3% of the sample.
Adjusting for population and using the USA as reference, the number of highly cited scientists born was at least 75% of the expected number in only 8 other countries. It was estimated that approximately 94% of the expected top scientists worldwide have not been able to materialize themselves due to various adverse conditions.
Conclusions: Countries without a critical mass of native scientists lose most scientists to migration. This loss occurs in both developed and developing countries. The vast majority of the scientific potential worldwide has been stifled by various adverse conditions. Scientific deficit is only likely to help perpetuate these adverse conditions and widen the gap between rich and poor countries.