Healthcare is facing great challenges and psychiatric care is no exception. Extensive attempts to improve quality are made. It is essential to use methods that enable learning from experience, to improve performance. The core feature of Statistical Process Control (SPC), the control charts, are in use in various settings to enable learning and to support quality improvement work, but its use in psychiatric settings are scarce. This master´s thesis explores the usefulness of control charts, in quality improvement work. This was done in a case study at a department of psychosis by addressing two questions related to: a) control chart’s contribution to knowledge on if, when, where and how changes occur, and 2) how usefulness of control charts is perceived at the department. Control charts were applied to important variables and development officer’s and manager’s thoughts on usefulness were analysed using pattern matching. The use of charts shows shifts and differences between wards related to ongoing improvement projects. There is a readiness to start using control charts. The perceived usefulness matches the benefits and challenges identified in literature. Control charts as a tool supporting continuous improvement work in a psychiatric context, has a great potential still awaiting its use.