Border Security: Apprehensions versus Attempted Crossings

    In mid-February, Homeland (DHS) Secretary Janet Napolitano and Delaware Senator Tom Carper visited Arizona to observe border security operations at the well known Mariposa Port of Entry.  Carper chairs the Homeland Security and Governmental Affairs Committee, and he conducted the tour with Napolitano as part of his committee's oversight function.  Napolitano and Carper issued a joint statement after the trip that included this claim about a precipitous drop in attempted illegal border crossings during the first four years of the Obama administration:

Over the past four years, the Obama Administration, working together with Congress, has dedicated historic levels of personnel, technology, and resources to the Southwest border, and undertaken an unprecedented effort to transform our nation's immigration enforcement systems into one that focuses on public safety, border security, and the integrity of the immigration system.  

Attempts to cross the border illegally, as measured by U.S. Border Patrol apprehensions, totaled nearly 365,000 nationwide in FY 2012, representing a nearly 50 percent decrease since FY 2008 and a 78 percent decrease from their peak in FY 2000.

    The key phrase is "as measured by U.S. Border Patrol apprehensions."  Since attempted crossings are, of course, impossible to track accurately, this statement makes the assumption that attempts mirror apprehensions - in other words, attempts are only counted if those crossing are caught.  Not only is this highly improbable, it opens the door for manipulation of the numbers or even manipulation of enforcement efforts themselves.  Lax enforcement of border security would result in lower apprehensions and therefore lower reported attempts when in fact the lax enforcement would likely result in a higher success rate for those attempting to enter the U.S. illegally.

    This apprehensions-equals-attempts formula is counterproductive and probably misleading.  Looking at airport security as a parallel, if the Transportation Security Administration (TSA) were to see a decrease in the number of weapons being carried into airplanes, that would not automatically mean fewer attempts were being made to carry weapons on board.  On the contrary, it may indicate more success by violators in hiding such weapons, a decline in thoroughness by TSA personnel, or lack of effective search techniques to find new varieties of more easily hidden weapons.  Any solace gained from a report of a decline in weapons seizures by the TSA apart from other factors to explain the decline would be rather cold comfort.

    Not only does this proxy method suffer from practical and logical fallacies, the DHS has itself disavowed its validity as recently as 2011.  In a July 2011 DHS Fact Sheet, a section entitled "Defining Border Apprehensions" says the following [emphasis added]:

Apprehension data collected by DHS represent events, not individuals. The total number of apprehensions during a specific period will be greater than the total number of unique individuals apprehended because some individuals will have been apprehended more than once. The relationship between the number of border apprehensions to either the number of attempted illegal entries or the number of successful illegal entries is unknown. 

    The same document goes on to note that the "decrease in apprehensions ... may be due to a number of factors including changes in U.S. economic conditions and border enforcement efforts." The statement from Napolitano and Carper was silent on economic and other possible factors.

    Another problem presented by this proxy method of counting attempts is the implications for the other statistics quoted later in the press release:

Additionally, from FY 2009 to 2012, CBP and ICE seized 71 percent more currency, 39 percent more drugs, and 189 percent more weapons along the Southwest border as compared to FY 2005 to 2008.

    Applying the earlier logic, this would mean drug traffic across the border increased by 39 percent, and weapons traffic increased a whopping 189 percent.  Those would not be statistics that DHS would be anxious to report using the apprehensions-equals-attempts formula. But by choosing to tout success in reducing attempted border crossing with a dubious methodology, the DHS has inadvertently implied those disturbing conclusions.

    None of this amounts to direct evidence that the DHS is manipulating statistics or that the results derived from the numbers are somehow wildly inaccurate.  But at a time when the Obama administration is seeking to push through "comprehensive immigration reform," demonstrating a secure border, a pre-condition to immigration reform for many on the right, is certainly in its interest.  The apprehensions-equals-attempts proxy does not provide the assurance that the secure border pre-condition has been met.