Surveys don't estimate border-crossing attempts well
Surveys don't estimate border-crossing attempts well, the National Research Council says in a report released Nov. 9.
Estimates are important in order to discern whether border protection has worked, and the number of apprehensions alone doesn't tell the whole story because that information says nothing about migrants who elude capture.
Some major surveys in the United States and Mexico, such as the Census Bureau's American Community Survey, do collect some information about migration. But no major surveys were designed to study migration in particular, the NRC says.
Since migration is a relatively rare occurrence, surveys of migration present a challenge because they must have a large sample size. To produce precise estimates of border-crossing attempts in the geographic regions into which the Border Patrol divides the southwest border, survey makers would need even larger sample sizes.
And since migration dynamics change often, as border crossers adapt to enforcement strategies and other factors, survey data would also have to be collected, analyzed and released very quickly.
The NRC says that because of surveys' limitations, the Homeland Security Department should limit its investment in improvements to current surveys or the development of new ones.
That said, migration survey data could be more useful in combination with the data DHS collects internally on apprehensions and other activities. But DHS would not provide its data to the NRC because of concerns about sensitive law enforcement information.
The report says that allowing independent scholars to evaluate the quality of DHS's information would help the department reach a better understanding of border activity.
- go to the report webpage
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