The digital divide has persisted over the life of the Internet.

National Bandwidth Potential, a novel Internet diffusion metric indicating application feasibility, shows a persistent digital access divide.

People have been trying to measure the global diffusion of the Internet and the digital divide between rich and poor nation for twenty five years. The first to do so was Larry Landweber, who noted whether or not a nation had an Internet (or other) connection. It was a binary metric -- yes or no -- and it was suitable to its time because there were only a handful of users who were restricted to teaching and research, using a few applications like email, file transfer, news groups and remote login.

1991 Internet diffusion (purple)

Five years later, the Internet had many more users and applications in commerce, government, entertainment, etc., so my colleagues and I developed a multidimensional Internet diffusion framework. One of our dimensions was pervasiveness, based on the number of users of the Internet per capita.

That made sense in 1995 since there were relatively few applications available for the slow dial-up connections of the time. A few people had faster ISDN or DSL connections and an organization might connect over a faster digital link, but most users were running the same few applications over analog phone lines.

Today, users per capita is pretty well meaningless. A Cuban who accesses email using a 2G cell phone and a Google Fiber user who has symmetric gigabit access to multiple computers and devices on a home LAN are clearly not equal.

To some degree, we anticipated this sort of thing via the connectivity infrastructure dimension in our framework. It considered international and intranational backbone bandwidth, Internet exchange points and last-mile access methods, but it was an imprecise measure -- mapping a nation into five levels -- and data was not readily available. (Our case studies typically required two weeks of in-country interviews).

Skipping ahead twenty years, a paper by Martin Hilbert uses an interesting diffusion metric -- nationally installed bandwidth potential (BP), which is a function of the number of telecommunication subscriptions (fixed and mobile), the kind of access technology per subscription (cable, DSL, GSM, etc) and the corresponding bandwidth per access technology. Their estimation of the latter is quite complex, taking factors like data type, upload/download speed, compression, etc. into consideration. The methodology is described in a ten page supplement to the paper. (It is behind a paywall -- let me know if you would like a copy).

Hilbert computed the BP of 172 countries from 1986 to 2014 and observed that the digital access divide is persistent. It is true that wireless connectivity is relatively inexpensive and mobile Internet use is growing rapidly in developing nations, but it is just as clear that many applications are precluded by the speed and form factor of mobile devices. A WhatsApp chat with a friend is not the equivalent of watching a high-resolution movie on a large screen TV and I am confident that Hilbert did not conduct his research or write the paper I read on a mobile phone. Even reading this blog post, following its links to other documents and taking notes on it would be tedious on a phone.

I expect this imbalance to persist because improved technology is costly and it enables ever more complex, demanding applications. The only trend I see that may in part reduce this feasible-application gap is the move to server-side processing for big data and AI applications, but even then interaction and the display of results will require bandwidth.

Hilbert's data also shows global shifts in application feasibility. As shown below, BP dominance has shifted from the US in the early, NSFNET days to China today. Korea has joined the top ten and the shares of Japan and Western Europe have dropped. The share of the bottom 162 countries rose slightly in 2001, but had fallen below the 1986 level by 2014.

Ten countries with most installed bandwidth potential

Income differences explain much of the persistence of the digital divide, but policies regarding Internet infrastructure ownership and regulation are also important. For example Estonia ranks 40th in the world in GDP per capita, but is ranked 20th on the International Telecommunication Union ICT Development Index.

Policy choices may play an even larger role among the top ten nations. The US ranks 9th in GDP per capita and Korea is 30th, but my son, who lives in Korea, pays $22 per month for symmetric, 100 mbps connectivity and has a choice of several competing Internet service providers. I live in the US and pay considerably more than he does for considerably slower service and have no ISP choice -- I am stuck with Time Warner Cable.

While we are waiting for enlightened policies, we can hope for technical change like the OneWeb and Spacex satellite Internet projects.