The first thing I want to dispel and if you just bring home one thing from this is this idea there is a very powerful and very wrong way of thinking about the US economy, labor market, and what immigrants do that. And this very powerful and very wrong way comes essentially straight out of Malthus. The idea that we live in a world that has a very strongly constrained productive capacity like land and more people you pile up the more the marginal productivity of people goes down. If you think of immigration as a sudden change of a lot of people in constrained resource place, then this will make you say migrant have to displace native, migrant has to push down the wage of natives. The real understanding of our research, not just in immigration economic but in growth economic, in trade, in economic geography, is that it's almost the opposite in fact. Which is when you have more skills, more people, more varieties of ability, more idea in a place close by.more you produce per person, because what matter for our economy is not how much land you produce. Land is not that relevant in production. Is how many ideas you have, how many abilities you have, how more complex is your set of skills. So the way of understanding the effect of immigration is that the economics that you should apply in the labor market is an economic in which a skill, ideas enterpreneurship, creativity, innovation play a key role. And if that's true, more people, and in particular, as I've showed you, out of which a lot of them are also highly educated, this is going to have a massive positive impact on firm, productivity, variety of things. So it's really hard to argue that the most developed country for most developed countries, the Malthusian, a world that maybe works in agriculture in sort of early society is a group good representation of reality. But really, when people say, immigrants steal your job, immigrant push native out of the labor force, they have the Malthusian model in your mind. So in a way that everybody who has taken ECON 1 can think about. THe relationship between productivity and density of people in employment, in a Malthusian world is one in which there is a fixed factor. And as a consequence of when you increase the number of people, immigrant bring number of worker from here to here, you have to push down the marginal productivity. And this world goes with more crowding, more congestion in production, more competition. Instead, in the world in which that we have seen in economics in the last 30 years, the world, I don't know, in which Paul Romer who was the growth economist wins the Nobel Prize, because he says that ideas are really what makes the growth, in which Paul Krugman wins the Nobel Prize in trade and geography because he says his specialization is a variety, is concentration that increases productivity knows who in their world. When you have more people that work in an economy, this increases specialization, increases agglomeration economy as they're called, increases diversity of skill that you need to produce sophisticated goods, and so ultimately increases productivity. And so clearly in a very simple representation, more people,more immigrant, in particular, if they are different people, if they are educated and they have different skills, brings you up along the marginal productivity or along the productivity line. So the theory that more immigrant going to place hurt the wage of natives is really is really very little evidence to support of that type of idea. The second thing that I don't think people have appreciated a lot but the recent research has brought out in a very strong way is that immigrants have a much higher enterpreneurship rate than native do in the United States. What is an enterpreneurship rate? Essentially, is a per 1000 people, the probability that one of them creates a new firm and to create a new job through that firm. Now, you can ask why, why is it that immigrants are and I think that again, selection explains a lot. And all of the characteristics that make you a good enterpreneur are similar probably to the characteristic that brought you to leave your country to begin with. You are probably less risk averse, you have, you fear change a little bit less, you are a little bit more adaptable. These firms that are created by by immigrants, of course employ a lot of natives as well. So, in a sense, if you think that the scars factor in a country is enterpreneurship, having more people who could create who have ideas, who have initiative, who have risk- taking attitude to create the firm can be the most important thing to generate some other jobs. So in this form, in this way, you see how immigrant can be actually very important in creating a generating jobs. Just out of their intrapreneurial impact, you can estimate this correspond to several hundreds of 1000s of jobs that are created in firms which are started by natives, so again, go back to Malthus. If the important factor to produce was land, fixed, more people generate less, but if the important factor to produce our idea, enterpreneurship, creating then more people and more of these kinds of people, increases really the possibilities of everybody.