There are many different methods of measuring quality of life in terms of health care, wealth, and materialistic goods. However, it is much more difficult to measure meaningful expression of one's desires. One way to do so is to evaluate the scope of how individuals have fulfilled their own ideals. Quality of life can simply mean happiness, the subjective state of mind. By using that mentality, citizens of a developing country appreciate more since they are content with the basic necessities of health care, education and child protection. According to ecological economist Robert Costanza: Human Development Index Perhaps the most commonly used international measure of development is the Human Development Index (HDI), which combines measures of life expectancy, education, and standard of living, in an attempt to quantify the options available to individuals within a given society. The HDI is used by the United Nations Development Programme in their Human Development Report. However, since year 2010, The Human Development Report introduced an Inequality-adjusted Human Development Index (IHDI). While the original HDI remains useful, it stated that "the IHDI is the actual level of human development (accounting for inequality), while the original HDI can be viewed as an index of 'potential' human development (or the maximum level of HDI) that could be achieved if there was no inequality." World Happiness Report The World Happiness Report is a landmark survey on the state of global happiness. It ranks 156 countries by their happiness levels, reflecting growing global interest in using happiness and substantial well-being as an indicator of the quality of human development. Its growing purpose has allowed governments, communities and organizations to use appropriate data to record happiness in order to enable policies to provide better lives. The reports review the state of happiness in the world today and show how the science of happiness explains personal and national variations in happiness. Developed again by the United Nations and published recently along with the HDI, this report combines both objective and subjective measures to rank countries by happiness, which is deemed as the ultimate outcome of a high quality of life. It uses surveys from Gallup, real GDP per capita, healthy life expectancy, having someone to count on, perceived freedom to make life choices, freedom from corruption, and generosity to derive the final score. Happiness is already recognised as an important concept in global public policy. The World Happiness Report indicates