The Claremont Colleges Library conducted direct rubric assessment of Pitzer College First-Year Seminar research papers to analyze the impact of diverse levels of librarian course collaborations on information literacy (IL) performance in student writing. Findings indicate that progressive degrees of librarian engagement in IL-related course instruction and/or syllabus and assignment design had an increasingly positive impact on student performance. A secondary indirect analysis of librarian teaching evaluations and self-perceived learning gains by students and faculty showed no correlation to rubric IL scores, suggesting the importance of "authentic" assessment in determining actual learning outcomes. This mixed-methods study presents findings in each area and examines their implications for effective IL course collaborations.