School librarians impact on student achievement research

The Pennsylvania School Library Association's research determined what school library infrastructure contributes most to student achievement, the costs and benefits associated with it, and what’s needed to develop students with 21st-century learning skills. Although more than two decades of similar research has been conducted in over 22 states, the Pennsylvania study uncovered the following new and significant findings:
- Quality school library programs significantly impact the most vulnerable students. 
- Writing scores are more positively impacted than reading scores.
This is the first statewide study to assess the roles of librarians in teaching the American Association of School Librarians’ (AASL) Standards for the 21st-Century Learner as well as Common Core standards.  
Staffing remains the key factor. This study suggests that there’s no substitute for a full-time, certified school librarian who’s fully engaged in the teaching and learning process.
Kachel, D., & Lance, K. (2012).   Pennsylvania School Libraries Pay Off: Investments in Student Achievement and Academic Standards.