And so, you see, the sky is, indeed, green

Via Tyler Cowen of Marginal Revolution, another new study - well, "working paper" - assuring us yahoos that "there's nothing to see here" when it comes to millions of "guests" that flood in from the south each year.

Because U.S. and foreign born workers belong to different skill groups that are imperfectly substitutable, one needs to articulate a production function that aggregates different types of labor (and accounts for complementarity and substitution effects) in order to calculate the various effects of immigrant labor on U.S.-born labor.

Uh-huh. It goes on...

We introduce such a production function...contrary to the findings of previous literature, overall immigration generates a large positive effect on the average wages of U.S.-born workers. [Emphasis mine]

That's one helluva production function - one that could explain how you can raise wages by increasing the labor pool by a million people per year. Or you could ask a landscaper how's business and get a different perspective.
Another referenced paper in Tyler's post also pooh-poohs the crass notion that masses of low-skilled immigrants might negatively impact our own low-skilled citizens. But the paper has a very revealing passage on the effect of mass low-skilled immigration on technological investment

...the adoption of advanced technologies by individual plants is significantly reduced by the presence of a greater relative supply of unskilled labor...More work is clearly needed to better understand how firms choose which technologies to use and whether the choice is influenced by the relative availability of different skill groups. [Emphasis mine]

Ya think!? Not in that study anyway. The author quickly returns to the more comforting "sky is green" theme of his study. Reminds me of the old Steve Martin/SNL skit "Theodoric of York: Medieval Barber":

Wait a minute. Perhaps she's right. Perhaps I've been wrong to blindly folow the medical traditions and superstitions of past centuries. Maybe we barbers should test these assumptions analytically, through experimentation and a "scientific method". Maybe this scientific method could be extended to other fields of learning: the natural sciences, art, architecture, navigation. Perhaps I could lead the way to a new age, an age of rebirth, a Renaissance! [thinks for a moment] Naaaaaahhh!