This paper presents an approach to asses ICT investments in public administrations. The public sector bears great potential for business process optimization through ICT. However, these possibilities remain largely unexploited since the effects of ICT on the processes are not clear to decisions makers. To asses this impact all processes of a public administration, the process landscape, have to be taken into account. The PICTURE modeling method has been proposed as a way to efficiently model the whole process landscape. Based on the knowledge captured with those process models, the impact of certain ICT functionalities on the processes can be analyzed. ICT investment decisions become more transparent towards the political leadership. This paper has two research objectives: First, an architecture for an automated evaluation of ICT investment decisions is introduced. Second, the practical feasibility of the architecture is shown based on an investment decision for a document management system.