I'm sure that lots of things happened in 2004. For instance, the productivity surge that began in the 1990s ended about 2004. Here's something else that happened (from an NBER study): In response to concerns that foreign workers were taking jobs from Americans, especially in high-technology fields, Congress cut the annual quota on new H-1B visas from 195,000 to 65,000, beginning with fiscal year 2004. A study by Anna Maria Mayda, Francesc Ortega, Giovanni Peri, Kevin Shih, and Chad Sparber, based on data for the fiscal years 2002-09, finds that the reduced cap did not increase the hiring of U.S. workers. Could this have contributed to the productivity slowdown? Hard to say, but it certainly did not
Scott Sumner considers the following as important: Labor Mobility, Immigration, Outsourcing
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