The departure point of this paper is the use of visualization as a tool in action case research. In such research, the researcher seeks a balance between interpreting qualitative data and intervening to solve the problem of the research partner. The communicative and knowledge aspects of visualization are highlighted. The research partner in this research, Flower Systems Ltd. (FSL), is a software company that has developed the ISOX 2000 document management system especially to meet the needs of social services in local governments. Over the last year, employees at various social service agencies have complained about the usability and user friendliness of ISOX. In the action case research two kinds of results are expected: concrete results, as in taking action in a problem solving context (here, the usability problem with ISOX), and conceptual results, as in listing proposed changes to a theoretical framework. The question raised in this paper is: What are the benefits of using visualization as a tool for building interpretations and understandings that are shared by both researchers and practitioners? The concrete results of the collaboration are 1) a more user-friendly, redesigned version of ISOX based on the use of different visualization techniques and 2) a change in how FSL works on redesign. The conceptual result is a list of proposed changes to the knowledge visualization framework, based on the empirical findings and theoretical framework regarding visualization