Studies show that librarian involvement in systematic reviews improves the quality and reproducibility of the literature search (Rethlefsen et al., 2015).
Rethlefsen ML, Farrell AM, Trzasko LC, Brigham TJ. Librarian co-authors correlated with higher quality reported search strategies in general internal medicine systematic reviews. Journal of clinical epidemiology. 2015 Jun 1;68(6):617–26. pmid:25766056