Sources of evidence may be internal or external and include published literature, guidelines, anecdotal stories from colleagues, information from a competitor, previous experiences with recipients, results from a local pilot, and other sources (Rycroft-Malone, Harvey, et al. 2002; Harvey and Kitson 2015; Stetler 2001).
The original CFIR (Laura J. Damschroder et al. 2009) elaborated on this construct, stating that though there is no agreed upon measure of “strong evidence,” there is empirical support for a positive association with dissemination, though evidence is mixed (Dopson et al. 2010). Though strong evidence is important, it is not always dominant in individual decisions to adopt nor is it ever sufficient (L. Fitzgerald and Dopson 2006). The PARiHS model lists three sources of evidence as being key for uptake: research studies, clinical experience, and previous patient experience (Rycroft-Malone, Harvey, et al. 2002), and Stetler adds the possibility of other sources that appear to be credible (Stetler 2001). Externally and internally generated evidence, including experience through piloting (see Implementation Process: Doing), may be combined to build a case for implementing an innovation (Stetler 2001). The more sources of evidence used, the more likely innovations will be taken up (A. Kitson, Harvey, and McCormack 1998; Rycroft-Malone, Kitson, et al. 2002).