When is an immigration crisis not an immigration crisis? When people who do not live where it is happening change the definition of an immigration crisis.

A new paper from Rice University's Baker Institute for Public Policy examines historical immigration data, the "push" and "pull" factors currently motivating Mexicans and Central Americans to migrate to the U.S. and then attempts to explain why current undocumented immigration streaming across the Mexican border is not a crisis. 

"In recent months, print and television journalists have presented the American public with a 'crisis' of illegal immigration on the U.S.–Mexico border," said Tony Payan, a Baker Institute Fellow for Mexico Studies. "Much of this recent discussion has centered on Central American children traveling alone and on allegations that they are responding to motivations created by the Obama administration's Deferred Action for Childhood Arrival policy. The word 'crisis,' however, can have alternative meanings. If a 'crisis' of undocumented immigration means a historically large or very rapidly growing flow of undocumented immigrations, the overall national evidence shows today that there is no such crisis. Border Patrol apprehensions of undocumented immigrants attempting to cross the U.S.–Mexico border have in fact plummeted and remain far below levels a decade earlier."

Since the number of illegal immigrants is unknown, the paper cites that the overall number of apprehended by the U.S. Border Patrol in 2013 was about 64 percent below that of 2004. Overall apprehensions had increased 26.5 percent between 2011 and 2013. Apprehensions were declining consistently before then, with 2011 being the trough year, the authors write. Principal determinants of this decline likely include the almost doubling of Border Patrol personnel in 2004-2013 and then the Great Recession that has made America a lot less economically attractive.  

The authors acknowledge that Central American children traveling alone have surged but say that publicly available data for this category only go back to 2010 so it may have been even higher in previous years.

There are many dynamics, economic and social, that seem to have motivated additional unauthorized travel across the U.S.–Mexico border in the last few years, the authors conclude. "Finally, there is always the immigrants' ongoing calculation of the constantly changing probabilities of apprehension, remuneration and survival," they said. "The key with all of these variables, however, is to understand which tug in what direction and weigh them accordingly in order to understand the overall effect on migration wave — this is true for both push and pull factors. But given the statistics story we have presented, we can conclude that there is hardly an immigration crisis — something that would have been a different story around 2005."