To answer this question, we begin by considering the extent to which overall
poverty would have declined if the share of immigrants had increased over time but
immigrants and natives had kept same poverty rates as in 1979. We find that if the
level of poverty among immigrants had stayed the same as it was in 1979, the rising
share of immigrants would have increased the poverty rate from 12.3 percent
(1979) to 12.5 percent (1999), a number that is only slightly bigger than the actual
value of 12.4 percent. We also consider the effects of changes over time in the
fraction of immigrants who are poor. If we hold population shares and native
poverty rates constant at their 1979 levels, but allow poverty rates among immigrants
to vary across Census years, then the predicted overall poverty rate in 1999
is about 0.1 percentage points higher than its 1979 level. Although recent immigrants
are poorer than their predecessors, their fraction of the population is simply
too small to affect the overall poverty rate by much.