The professor from whom I learned the most in college used to tell us that economics is a mixture of little science, a fair amount of technique, and a lot of ideology. I would add that ideology, especially, abounds in public debate, albeit disguised as science, given that scientific and technical debate remains within the academic world. We have good examples in recent economic debates: the debate on the regional financing model and the debate on the impact of immigration.

The economic narrative against immigration is often based on the idea that most immigrants only find low-paying jobs, meaning they will end up receiving more from "our" welfare state than they contribute. They are, therefore, a bad deal. This argument would be economically irrefutable were it not for the fact that a large part of the local working population finds itself in the same situation. If immigrants represent a net cost to the public purse from the moment they arrive, this segment of the local population has had this cost since birth.

It's becoming a commonly accepted misconception that immigration makes the welfare state unsustainable. However, the data tells a different story: the autonomous communities with higher immigration rates have higher per capita tax and social security revenue than those with lower or no immigration. This is obviously not because the workers are immigrants or not, but because the communities with high immigration rates have higher employment rates, which they wouldn't have achieved with the native population alone.