Evidence that employers really care about internships

What do employers really look for in a resume?  To find out four researchers at three universities did a randomized study where they sent fictitious resumes to online job postings.  Each resume showed a college degree received in 2010 and one job held since then.  The resumes varied by major (half business and half liberal arts), GPA and whether the applicant held an internship in the same field as the opening.  

I was a bit surprised to see 17 percent of the resumes were invited for an interview; this strikes me as very high for an online application process.  But more importantly, what were the key variables in predicting who landed the interview?  It was not the major.  It was not the GPA.  It was whether or not the student had an internship!  Those with internships were 14 percent more likely to get interviews than those without.  

This may actually understate the true impact of internships because it does not include the most common scenario -- where the internship leads directly to a job.  So even though summer school starts tomorrow, don't give up on that internship yet!