Development economics focuses on improving fiscal, economic, and social conditions in developing countries. It considers factors like health, education, markets, and policies. Economic development is the growth of a nation's standard of living from low-income to high-income. Strategies for transforming developing economies vary due to differences in social and political backgrounds across countries. Common traits of developing countries include low productivity, dependence on agriculture, high population growth and unemployment. Economic growth increases production over time, while development improves life expectancy, education and reduces poverty. The Human Development Index ranks countries based on education, life expectancy and income levels.