Immigration, almost trivially, increases the size of the economy: more mouths to feed, more people to house, more demand for creature comforts. So, immigration increases jobs. Whether it creates more jobs than it consumes is a bit trickier. My money is on, "yes," but I suppose it will always depend on the details. I would also like to see a study; I'm sure someone must have done one.
The question is really: do you care that there is more wealth overall, or do you care that you personally are better off. Most sane people have no urgent desire to start cramming more people into their neighborhoods. What people want are higher standards of living, not the same or worse standards of living split among more people, even if the overall economy is 'bigger'. Many third world population booms are decimating quality-of-life, especially in places like Nigeria, India, and Brazil. The only people who benefit from a bigger overall population and economy at the expense of individuals being better off, are the people at the very top.
They want a bigger pie because then their companies have bigger markets to sell their goods. If it comes at the cost of increasing the population so that everyone else is individually poorer, they don't care. You can't become a billionaire in a country of only 100,000 people. There aren't enough people from whom wealth can be concentrated.
Yes, I read the article, and he does seem to imply that is the case with immigrants at the bottom level of skills. However, he also suggests that the total picture is much more complicated . . . it all depends on the details. My money is still on it being a net gain, overall.
