Life expectancy at birth is now considered as an indicator of the social, environmental, and economic development of a country. The main aim of development is to provide a better life for individuals and society in terms of development. In order to achieve this goal, countries are trying to develop policies, and efforts are being made to improve the living conditions of individuals. In this respect, health is one of the basic elements of a better life. 

Each baby born in the world’s most developed 24 countries is expected to live longer than 75 years. This length of life is less than 50 years in 45 underdeveloped countries. Differences in life expectancy between countries can be due to many reasons. In underdeveloped countries, food products, clean water, environmental hygiene conditions, and housing differences can be defined as the most important factors affecting the life expectancy of individuals. On the other hand, the rapid growth in income, unemployment, health expenditures, medical and insurance sectors and the increase in costs lead to a further diversification of the factors affecting the life expectancy in developed countries. When the data is analyzed, it is clear that the citizens of developed countries live longer than the citizens of undeveloped countries. The most important reason of that is the importance given to health investments in developed countries. These investments not only enable people in the country to use high-tech products in health care, but also reduce the number of patients per health worker. In addition, the increase in accessibility to health institutions allows people to live more healthily, which leads to a longer life expectancy in that country.

In this study, economic indicators which have an effect on life expectancy were investigated for OECD countries in the early 21st century. When the development levels and life expectancy of the countries are examined, it is seen that underdeveloped countries are significantly behind compared to developed countries in terms of life expectancy at birth. For this reason, it is of great importance to find out why length of life is higher in economically developed countries and it very important to investigate the economic indicators affecting this situation. 

When the economic literature is examined, it can be seen that there are some studies on the factors affecting life expectancy, but there are not enough studies investigating the link between life expectancy and economic variables. Also, it is clear that no study has as yet been conducted between direct economic variables and life expectancy. Moreover, in economic literature, there is also a lack of studies which use OECD countries as a sample. Finally, there is no other study which uses econometric methods. In this study, Panel Regression Analysis and Granger Panel Causality Analysis were applied for the 2000-2016 period. These analyzes explain the regression and the causality relationship between the variables. According to the findings, bi-directional causality was determined between life expectancy and unemployment rate. Likewise, bi-directional causality was determined between life expectancy and gross domestic product. Also, unidirectional causality relationship was determined from health expenditures to life expectancy. In addition, regression analysis revealed that health expenditures are the most important factor affecting the life expectancy in OECD countries. In line with the regression result, it is seen that there is a positive and significant correlation between life expectancy and health expenditure. This result reveals the importance of investments in health services and the importance of health expenditures. Also, it shows that the life expectancy can be improved by investments and technologies in the health sector. In terms of development, providing a better life to individuals and society is possible when the health expenditure of the country increases.