In their systematic review of clinical library (CL) service evaluation, Brettle et al. summarize evidence showing that CLs contribute to patient care through saving time and providing effective results.  Pointing out the wisdom of using evaluation measures that can be linked to organizational objectives, they advocate for using the Critical Incident Technique to collect data on specific outcomes and demonstrate where library contributions make a difference.  In the Critical Incident Technique, respondents are asked about an “individual case of specific and recent library use/information provision rather than library use in general.”  In addition, the authors point to Weightman, et al.’s suggested approaches for conducting a practical and valid study of library services:

• Researchers are independet of the library service.
• Respondents are anonymous.
• Participants are selected either by random sample or by choosing all members of specific user groups.
• Questions are developed with input from library users.
• Questionnaires and interviews are both used.

Brettle, et al., “Evaluating clinical librarian services: a systematic review.”  Health Information and Libraries Journal, March 2010.  28(1):3-22.

Weightman, et al., “The value and impact of information provided through library services for patient care: developing guidance for best practice.”  Health Information and Libraries Journal, March 2009.  26(1):63-71.