Calculating a reliable number for a segment of the population that generally wants to hide from officials is very difficult, but it’s politically very important to know more or less how many illegal immigrants there are, and whether their number is increasing or decreasing. There’s a whole lot of populist rhetoric floating around, especially regarding jobs and crime, and passions are often inflamed. Knowing how many illegal immigrants there are – more or less – allows us to quantify the real effects on employment and crime, and to deflate some of the rhetoric.
Immigration is a human rights issue in several respects. Immigration is often a way for people to escape human rights violations (such as poverty or persecution). And upon arrival, immigrants – especially illegal immigrants – often face other human rights violations (invasion of privacy, searches, labor exploitation etc.). The native population may also fear – rightly or wrongly – that the presence of large groups of immigrants will lower their standard of living or threaten their physical security. Illegal immigrants especially are often accused of pulling down wages and labor conditions and of creating native unemployment. If we want to disprove such accusations, we need data on the numbers of immigrants.
So how do we count the number of illegal immigrants? Obviously there’s nothing in census data. The Census Bureau doesn’t ask people about their immigration status, in part because such questions may drive down overall response rates. Maybe in some cases the census data of other countries can help. Other countries may ask their residents how many family members have gone abroad to find a job.
Another possible source are the numbers of births included in hospital data. If you assume a certain number of births per resident, and compare that to the total number of births, you may be able to deduce the number of births among illegal immigrants (disparagingly called “anchor babies“), which in turn may give you an idea about the total number of illegal immigrants.
Fluctuations in the amounts of remittances – money sent back home by immigrants – may also indicate trends in illegal immigration, although remittances are of course sent by both legal and illegal immigrants. Furthermore, it’s not because remittances go down that immigrants leave. It might just be a temporary drop following an economic recession, and immigrants decide to sweat it out (possibly supported by reverse remittances for the time of the recession). Conversely, an increase in remittances may simply reflect technological improvements in international payment systems.
Perhaps a better indicator are the numbers of apprehensions by border-patrol units. However, fluctuations in these numbers may not be due to fluctuations in immigration. Better or worse performance by border-patrol officers or tighter border security may be the real reasons.
So, it’s really not easy to count illegal immigrants, and that means that all rhetoric about illegal immigration – both positive and negative – should be taken with a grain of salt.
More posts on this series are here.