I'm ambivalent about the concept of "evidence" for much of the change and improvement work we do in healthcare because so many of the concepts and processes are contested. However, that doesn't stop me checking for evidence and testing my own prejudices.
There are a number of papers and publications which touch on the topic of readiness for change.
Review: Conceptualization and Measurement of Organizational Readiness for ChangeA Review of the Literature in Health Services Research and Other Fields
Weimer, Amick & Lee
All literature reviews need to be considered as a service to humanity. This one covers the concept of readiness for change in healthcare and reviews 43 instruments in use.
Assessing organisational readiness for change: use of diagnostic analysis prior to the implementation of a multidisciplinary assessment for acute stroke care