In 2012, the United Nations agreed a series of goals to transform the world by 2030. These include eradicating poverty, ending hunger, and providing health care and education for all people. These so-called sustainable development goals are ambitious and challenging; achieving them will be hard.

One of the primary challenges is measuring progress. That requires some objective method of assessing poverty, health, and well-being. In the developed world, this is done on a regular basis with tools such as economic surveys, population censuses, and so on.

However, these processes are time-consuming and expensive. Many developing countries simply don’t have the resources to carry them out. What’s more, surveys and censuses are almost impossible to conduct when there is civil unrest, disease, or famine. So an important goal is to find another way to measure conditions in these places in an effective and reliable way.

In recent years, researchers have begun to study how certain kinds of information flow through networks in countries around the word and how this might be a proxy for real-world conditions. For example, the way people purchase airtime for their mobile phones is powerful proxy for their socioeconomic status.

So an interesting question is whether this kind of study can largely replace the traditional methods of determining the socioeconomic status of a nation and of consequently measuring progress toward the U.N.’s goals.

Today we get an answer of sorts thanks to the work of Desislava Hristova at the University of Cambridge in the U.K. and a few pals, who have investigated how networks of digital and physical flows can provide insight into the state of nations. The answer, they say, is that these networks provide surprisingly detailed insight that is relatively cheap to garner.

These guys begin with several well-known networks showing the flow of goods and information around the world. These include the world trade network, the network of international flights, the international migration network, and the IP traceroute network showing the topology of the Internet.

In addition, they construct, for the first time, an international network showing the way post flows around the world. They do this using electronic postal records from 201 countries collected by the Universal Postal Union since 2010. In that time, a total of over 14 million items were posted.

Hristova and co constructed this new web using the countries as nodes. If an item had been sent from one country to another, they drew a link between those nodes. In total this web has some 23,000 connections, which is 64 percent of all possible connections. That’s an extremely dense network—more than half the countries have links to more than 100 others.

Interestingly, the volume of postal flows has been increasing steadily since 2010 because of the increase in e-commerce and the items bought in this way being sent through the post. For that reason, Hristova and co argue that postal flow mirrors this kind of economic behavior. “This positions postal flows as a sustainable indicator of socioeconomic activity,” they say.

Other networks also play the same role as proxies of important socioeconomic indicators. The global trade network shows the number and value of products traded between countries and so is an obvious choice as a proxy of economic health. The international flight network is made up of all passenger and freight flights between countries and so is reflects the economic and social links between them. The IP traceroute network shows the topology of the Internet and therefore reveals the links between countries through the perspective of digital infrastructure.

In total Hristova and co use six networks of physical and digital flows around the world. A key part of their work is to look at the combined effects of these networks. “Our hypothesis is that countries that are paired together in communities across more networks are more likely to be socioeconomically similar,” they say.

That’s important because it means that if one network only partially covers a region, then another can help plug the gaps in the corresponding socioeconomic understanding. This process of placing one network on top of another is called multiplexing. And to capture its effect, Hristova and co have created a metric called “global degree” that takes the influence of all the networks into account.

To test how well it works, they compared how each network correlates with a number of standard indicators of socioeconomic status such as GDP per capita, life expectancy, the Corruption Perception Index, happiness, number of mobile phone users, and so on.

Various networks correlate well with specific indicators. For example, the GDP per capita and life expectancy most closely correlate with the postal, trade, and IP weighted networks. (Curiously, the new postal network correlates strongly with happiness.)

However, the measure that is most powerfully predictive is the team’s new indicator—the global degree. “Looking at how well connected a country is in the global multiplex can be more indicative of its socioeconomic profile than looking at single networks,” they say.

That’s interesting work that could have a profound influence on the way economists, social scientists, and policymakers view the world and how it is changing. “We have shown how both global digital and physical network flows can contribute to support a better monitoring of sustainable development goal indicators,” say Hristova and co.

And they point out this type of approach is likely to become even more accurate in the future, as it becomes possible to track individual items more easily with technologies such as the internet of things.

If the U.N. is to effect change in the ambitious way it intends, it must have a way to measure standards of health, wealth and life in general. The work of Hristova and co is clearly an important step in this direction.

Ref: arxiv.org/abs/1601.06028: The International Postal Network and Other Global Flows ss Proxies for National Well-Being