worldwide inequality in production of systematic reviews

background: investment in science is vital for the development and well-being of societies. this study aims to assess the scientific productivity of countries by quantifying their publication of systematic reviews taking the gross national income per capita (gnipc) into account. methods: medline and isi web of science were searched for systematic reviews published between 1st january 2006 and 31st december 2010. the productivity of each country was quantified by exploring the authors’ affiliation. the gnipc was used according to the world bank report. concentration index (ci) was calculated as the index of inequality.  results: ci of percentage of systematic reviews as a function of percentage of countries ranked by gnipc was 0.82 which indicates inequality in production of systematic reviews in pro rich countries. countries with high income produced 206.23 times more systematic reviews than low income countries, while this ratio for lower middle and upper middle countries was 9.67 and 12.97, respectively. the highest concentration index was observed in clinical sciences (0.76) and the lowest in public health (0.61). conclusion: this study demonstrates a significant gap between industrialized and non-industrialized countries in the production of systematic reviews. addressing this gap needs tremendous national and international efforts.