Wiki projects can be edited by everyday web users directly within the web browser. Consequently, undesirable contributions like vandalism and spam cannot be ruled out. In this paper, Managed Wikis are introduced as a new approach to avoid such undesirable contributions. Editing rights are assigned according to author reputation, the quality of articles and the occurrence of patterns of suspicious edits. In the paper, the concept of Managed Wikis is evaluated by means of a simulation on the basis of Wikipedia data. The analysis proves that undesirable contributions are blocked effectively. In contrast, desirable contributions are rarely affected by the editing rights restriction. The concept of Managed Wikis addresses open as well as corporate wiki projects where undesirable edits cause significant harm. Furthermore, it can be applied to make traditional websites accessible for the web community
