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.
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.© MPI for Demographic Research (Phys.org) -- For the first time comparable migration data is available for almost every country of the world.To date, records were incompatible between nations and especially by gender and age, nonexistent.Emilio Zagheni from the Max Planck Institute for Demographic Research (MPIDR) in Rostock, Germany, 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Where estimates of demographic flows exist, they are often outdated and largely inconsistent, says MPIDR researcher Emilio Zagheni.
There is also no clear agreement between nations on how to actually define a migrant.
Official migration data is outdated and inconsistent Global internet data does not have these drawbacks, says Zagheni.
In addition to the date and geographical origin of each message they compiled the self-reported birthday and gender of the sender.
The curves show those who sent most of their emails from the U. between September 2009 to June 2010 but consistently wrote the majority of their messages from abroad between July 2010 and June 2011.
Emigration unveiled: by analysing millions of emails the first consistent figure of those emigrating from the USA was made possible.