The United Nations Development Pro- gramme (UNDP) uses the Human Development Index (HDI) in an attempt to summarize in one number the progress in health, education, and economics of a coun- try. The number of cell phone subscribers per 1000 people is positively associated with economic progress in a coun- try. Can the number of cell phone subscribers be used to predict the HDI

I'm not sure that the number of cell phones users per 1,000 people can be a good economic indicator. E.g. there are currently more than 1.6 billion cell phone users in China, which means that some people obviously use more than 1 cell phone (Chinese population is around 1.4 billion people). But China's HDI is 0.752 (2017) and that places China at the number 85 spot, which is really not a good place.

While other countries like Norway have less than 5 million cell phone users with a population of more than 5.35 million people. But Norway is ranked as the number 1 country in HDI.