Comparable migration data for almost every country of the world, which till now was incompatible between two nations and nonexistent especially by gender and age, is available for the first time.
Emilio Zagheni from the Max Planck Institute for Demographic Research (MPIDR) in Rostock, Germany, has provided for the first time provides a rich migration database by compiling the global flow of millions of e-mails.
“Where estimates of demographic flows exist, they are often outdated and largely inconsistent,” MPIDR researcher Emilio Zagheni said.
Official records are difficult to use for various reasons. Emigrants tend not to register after they move to a new country or do so very late. There is also no clear agreement between nations on how to actually define a migrant.
“Global internet data does not have these drawbacks.
“You are where you email,” Zagheni said.
Together with Ingmar Weber from Yahoo! Research Zagheni traced emails sent from Yahoo! accounts around the world to infer the residence of its sender.
Every device which sends email can be located at least at the country level by an internationally standardized code, the so-called IP address.
Zagheni and Weber analysed the countries derived from IP addresses for a set of messages sent by 43 million anonymous Yahoo! account holders between September 2009 and June 2011.
In addition to the date and geographical origin of each message, they compiled the self-reported birthday and gender of the sender.
When a person started sending e-mail from a new location permanently, it was assumed that he or she had changed residence. This way they were able to calculate rates of migration from and to almost every country in the world.
Only anonym zed data was used, so identifying individuals was impossible and no information about the recipients, the subject, or content of a message was accessed.
The findings of the study have been published in the ACM Web Science Conference Proceedings.