At The Corner, Mark Krikorian has an informative post on how the large-scale influx of less-skilled workers impacts the child poverty rate:

As I point out in my book, all the reasons are really just different facets of the one reason: Mass immigration is incompatible with a modern society. So my assumption was that David was right, but since I couldn’t expect Reihan just to take my word for it, my colleague Steven Camarota ran some numbers from the latest data. And, in fact, the results show pretty clearly that immigration plays a significant role in child poverty. Data gathered by the Census Bureau in 2009 (about income earned in the prior calendar year) show that in 2008, a total of 14.1 million children (under age 18) lived below the official federal poverty threshold. Of this 14.1 million, 4.4 million (31 percent) were either immigrants themselves or U.S.-born with at least one immigrant parent. The poverty rate for the children of immigrants is 26 percent, compared to 17 percent for the children of native-born parents.
The same data show that another 1.6 million Hispanic children with U.S.-born parents also live in poverty; most of these kids are the grandchildren of post-1960 immigrants. Looked at this way, the children and grandchildren of the current wave of immigration account for perhaps 43 percent of all children in poverty, compared to 32 percent of the nation’s total child population.

At least one critic, blogger Jim Henley, found my suggestion that family structure played at least as significant a role as immigration unconvincing. I’m still convinced that changes in family structure are an important driver. The Thomas-Sawhill shift-share analysis doesn’t capture, for the obvious reason that it would be very difficult to capture, the impact of assortative mating, which tends to intensify levels of household income polarization.

Mark’s findings are very useful. When I wrote the original post, I observed that certain U.S. jurisdictions and foreign countries with large foreign-born populations nevertheless had relatively low rates of child poverty. Part of this reflects the fact that New Jersey attracts a different pool of migrants from North Carolina or Georgia or California. And part of it reflects the fact that Sweden redistributes more generously and through different channels. That is, child poverty rates can be low despite a large influx of less-skilled workers if the society in question tolerates a much higher level of transfer payments.

So Mark is right to argue that the net burden imposed by various streams of migration should be taken into account when we devise our immigration policies. I’d add the native-born child poverty rate is troublingly high, as I think Mark would agree. One could argue that less-skilled native-born workers would have better employment prospects if the population of working-age migrants were smaller, though there is some dispute about this in the academic literature.