The documentation of the nursing process is an important, but often neglected part of clinical documentation. Paper-based systems have been introduced to support nursing process documentation. Frequently, however, problems, such as low quality, are reported and it is still unclear if computer-based documentation systems can reduce these problems. We therefore introduced a computer-based nursing documentation system on four wards of the University Hospitals of Heidelberg. We systematically evaluated its preconditions and its effects in a pre-test post-test intervention study. We combined objective data (e.g., based on quality checklists) with subjective data drawn from questionnaires and interviews. In this paper, we present preliminary results, focussing on detailed results from the first two wards.