Validation of a generic impact survey for use by health library services indicates the reliability of the questionnaire

BACKGROUND: A validated generic impact questionnaire can demonstrate how individual and groups of health libraries contribute to continuing education and patient care outcomes. OBJECTIVES: To validate an existing generic questionnaire for Knowledge for Healthcare, England by examining: (1) internal reliability; (2) content validity; and (3) suggest revisions. METHODS: Methods used included Cronbach's alpha test, simple data mining of patterns among a data set of 187 questionnaire responses and checking respondents' interpretation of questions. RESULTS: Cronbach's alpha was 0.776 (acceptable internal reliability). The patterns of responses indicated that respondents' interpretations of the questions were highly plausible, and consistent. The meaning of ‘research’ varied among different occupational groups, but overall, respondents could identify relevant personal and service impacts. However, users were confused about the terms that libraries use to describe some services. DISCUSSION: The analysis indicated that the questionnaire worked well for the two types of personal services (literature/evidence searches and training/e‐learning) frequently cited on the responses. Further research may be required for library assessment of the impact of other services such as digital resource services. CONCLUSIONS: The generic questionnaire is a reliable way of assessing the impact of health library and knowledge services, both individually and collectively.