For college students, it's that time again—hunting for a summer internship.
Internships have become increasingly important as job candidates attempt to stand out in a challenging job market. But the type of internship you land can make all the difference.
Paid internships markedly increase a student's chances of landing a job by graduation. But unpaid gigs provide little or no edge over not interning at all, according to a survey by the National Association of Colleges and Employers.
(Read more: Rallying cry against unpaid internships grows)
In the association's most recent annual survey of students, conducted last spring, 63 percent with paid internships had landed jobs before graduation. Even accounting for gender and industry, just 37 percent of students with unpaid internships were that successful, barely more than the 35 percent of students with no internships who had landed jobs.
"The unpaid internship had no impact relative to having no internship, at least in terms of getting a job," said Edwin Koc, director of strategic and foundation research.
(Read more: Unpaid interns pose new challenge for job seekers)
The salary difference between paid and unpaid internships was also large: Those with paid internships who landed jobs got starting salaries averaging $51,900, well above the $35,700 offered to students with unpaid internships. (Students with no internships actually had a slightly higher starting salary—$37,100—but Koc said the difference is not statistically significant.)
Pay for internships can vary widely, from thousands of dollars a week at a tech company to a nominal amount at a small organization.
(Read more: Wall Street slips out of highest paid intern list)
Even so, many paid internships are at least as hard to land as the unpaid kind. So what's a student to do?
Career development offices on campus and academic advisors are a great place to start. They often have plenty of internship listings, and some of them may not be advertised widely.
Various websites also feature listings of available internships. For example, idealist.org lets users search for paid internships with nonprofits, filtering by industry and location. Simplyhired.com offers similar search capabilities for internships with for-profit employers, as does internmatch.com.