USA Visa Waiver Program is a specific program designed especially for the most developed countries; so if you are willing to apply for this program, you must check if your country is included in the selective list or not. The United States of America is running the program allowing permissions to the nations of different countries for different purposes. For example, if you want to come to the USA for a business trip, tourism or studies etc, you can stay over there up 90 days for which you are not supposed to have a visa.
Lots of Arab and Asian countries are not listed in this program, which means if you are the citizen or you have the nationality of those countries, your visa application will not be entertained at all.
There are lots of standards and parameters engaged used for the selected countries, for example high-income economy, which is calculated by the World Bank using different statistics like if a country meets the standards and parameters it is considered a wealthy country, whose gross national income was more than U US$12,475 during 2015.
Human development Index also known as HDI is another factor to determine the rank of a country. Information based on per capita income, education and life expectancy etc is collected which is then evaluated. If a country’s HDI is higher or the higher the HDI is the higher the ranking will be. Such countries are considered most developed countries.
So, if you are applying for Visa Waiver Program thinking you are from developed countries, please check the list. If you are not, then you will have to follow general procedure of applying for visa for which you will have to appear for the interview and convince the concerned person about your purpose.