For one perspective, see this article from Inside Higher Ed. More detail on that ethnographic research study (based in part on earlier work at the University of Rochester) is here and some of the published findings include:
• Widespread and endemic gaps in students' understanding of the basic concepts of academic research, including: (1) an inability to correctly read and understand citations, (2) little or no understanding of cataloging and information organization systems, (3) no organized search strategies beyond "Google-style" any word, anywhere searches, and (4) poor abilities in locating and evaluating resources (of all types).
• Students who had developed a relationship with a librarian reported high levels of satisfaction with the help provided, returned repeatedly for help other assignments, and recommend librarians to their peers.
• As librarians build relationships with teaching faculty, they will also build relationships with students. Administrators can also contribute to these relationships by supporting curricular initiatives that reinforce collaboration between librarians and teaching faculty, and that promote the participation of librarians throughout students’ course of study.