Purpose – This paper aims to evaluate a range of best practice knowledge management (KM) ideas used to manage knowledge resources. In total, four KM toolkits and 16 KM tools were tested over a five-year period (2008-2013), as part of a large-scale longitudinal change project. Each tool was assessed against an evaluative framework designed to test criticisms of KM: strategy, implementation and performance. The results provide empirical evidence about which KM tools work and which do not and why, and outcomes for practitioners, researchers and consultants. Design/methodology/approach – The case study organization participating in the study was selected because it was a knowledge-intensive organization, with an ageing workforce. An invitation and cover letter explaining the study were sent via email to all 150 engineering and technical staff at the case study organization. Therefore, the entire population was included in the study. Respondents were asked to attend training workshops. Following each workshop, respondents were asked to complete feedback in the form of learning journals and to be involved in work-place based trials of the KM tools. Both management and staff participated in the project. Findings – The results provide empirical evidence that KM can be used to manage knowledge resources. The highest rating toolkit was knowledge strategy, followed by knowledge measurement. The most value was created by using KM to introduce objectivity into future thinking (future capability requirements) and decisions when filling competency gaps (sourcing). The results tended to support criticism that KM is difficult to implement and identified the main barriers as participation located at the operational action research level, i.e. how do we make this work? Evidence that KM works was found in progress towards learning organization capacity and in practical outcomes. Research limitations/implications – The action research cycle and learning flows provide opportunities to examine barriers to KM implementation. The research also presents opportunities for further research to examine the findings in other organizational and industry settings, for example, the relationship between the KM toolkits and organizational change and performance, presents an important area for further research. Researchers might also consider some of the toolkits which rated poorly, e.g. knowledge creation (KC), and challenge these findings, perhaps selecting different KC tools for testing. The paper has limitations. It is based on a single case study organization, offset, to some degree, by the longitudinal nature of the empirical evidence. It is ambitious, and the findings may be controversial. However, the depth of the study and its findings provide rare longitudinal empirical evidence about KM, and the results should be useful for practitioners, researchers and consultants. Practical implications – There are many critics of KM. It has been described as overwhelmingly optimistic and managerial rhetoric; that its claims are false; and that many KM initiatives fail and, therefore, it does not create value for the firm, and its return on investment is unlikely. There is a shortage of empirical studies demonstrating an actual connection between KM and organizational performance. Despite widespread interest and growth in investment by practitioners and growth in research, KM needs validation to give people confidence in its value and some of the problems associated with implementation. This paper provides rare empirical evidence gathered from a five-year (2008-2013) large-scale longitudinal change project to address this gap. For practitioners, the research findings provide management with an evaluative framework to use when making decisions regarding KM. Originality/value – Much of the previous research on this topic looks at specific KM tools only, and often at one point in time. This study examined a wide range of best-practice KM tools as part of an integrated set of KM systems, launched at the same time and studied over five years. The study did not examine what the case study does in terms of KM. Instead, it deliberately introduced tools which were new to the case study organization. The results provide practical outcomes in terms of the effectiveness of KM when introduced to an organization as a system of integrated tools, and what happens in the five years that follow.