Wrong about immigration:
Though perhaps they're only drops in the ocean, a pair of white papers from the German economic research institute IZA recently consolidated the evidence, analyzing dozens of studies in many different countries over the past decade to see where most of them shook out. With a few outliers, results support the admittedly counterintuitive notion that -- as long as labor markets remain flexible -- immigration actually createsmore jobs and can push up wages for native-born workers. Here are the main reasons why that's true.
Wrong about supply side economics. Arthur "Laffer Curve" Laffer and colleagues created a grade, the ALEC-Laffer Economic Outcome Score, where the higher the score, the more supply-side friendly a country's policies are judged. The higher the score, the better, in their estimation. They make some claims about the scores that aren't supported by the evidence. Instead...
If there is any evidence, it suggests that a higher ALEC-Laffer Economic Outlook score is associated with a worse economic performance, as measured by 2013M01-2014M03 growth using the Philadelphia Fed’s coincident indices.
Wrong about strong welfare states reducing employment:
But then a funny thing happened [beginning in the late 90s] Europe started doing much better, while America started doing much worse. France’s prime-age employment rate overtook America’s early in the Bush administration; at this point the gap in employment rates is bigger than it was in the late 1990s, this time in France’s favor. Other European nations with big welfare states, like Sweden and the Netherlands, do even better.