Experts at companies that track internships generally agree that about 75 percent of college graduates will have taken at least one internship over the course of their four-year college career. This means that each year, more than a million four-year college students work as interns during the summer or during the school year. Recent surveys suggest that more than half of these interns are unpaid.

Add in interns from high schools, community colleges, university graduate programs, and even mid-career adults, and there may be as many as 2 million interns employed each year. Experts agree that the internship phenomenon was growing even before the Great Recession and has accelerated since. Yet, few can provide any information on the impact of internships, paid or unpaid, on the labor market or the wages and employment prospects of young people.

The U.S. Census Bureau and the Bureau of Labor Statistics provide the following useful data about internships: