This paper describes the experiences of the authors in conducting a three year evaluation of health system reform processes in the southern region of Adelaide and explores how the evaluation team utilised ‘insider’ and ‘outsider’ roles to establish and maintain trust and cooperation with stakeholders and informants in a turbulent policy environment. It uses the results of focus groups and interviews to analyse how the team was able to encourage the sharing of sensitive information and to examine the roles, responsibilities and risks to evaluators in carrying out a controversial evaluation. The importance and some means of finding a balance between insider knowledge and outsider objectivity in evaluation are discussed.