According to Gartner (http://www.gartner.com/it-glossary/digitalization/) "Digitalization is the use of digital technologies to
change a business model and provide new revenue and value-producing
opportunities; it is the process of moving to a digital business."
This definition focusses on the management or business perspective and can easily be widened onto a whole industry or economy and be analyzed in an economic way.
One of the first issues to solve then is how to measure the degree of digitalization of an industry or economy.