The Austrian health care system is influenced by a high dynamics of changes in the economic as well as the political environment. These changes are enhanced by the social expectation regarding quality and quantity of medical services. Therefore, modernisation of the infrastructure is inevitable, which can lead to privatisations and mergers. In the course of this master thesis the question is answered, if merged hospitals are more efficient than non-merged hospitals and if economies of scale and scope occur. Therefore the efficiency of all private and public non-profit acute care hospitals financed through the provincial health funds in Austria for the period from 2002 to 2013, is calculated. The efficiency analysis is implemented through Data Envelopment Analysis (DEA), a non-parametric approach based on linear programming. After a theoretical introduction the functionality of the DEA is explained. From the analysis of scientific papers conclusions for the model specifications, the selection of inputs and outputs as well as the applied methods are drawn. The used inputs and outputs are first analysed with regard to correlations and then with regard to outliers using scatterplots and super-efficiency. After the determination of the final set of hospitals the calculation of the efficiency is done through three different approaches. Within the first approach potential economies of scale are analysed and in the second approach economies of scope for merged hospitals are determined. And within the third approach only the efficient hospitals are analysed through super-efficiency for a more accurate comparison. Finally, changes of productivity over time are investigated using the Malmquist index and its decompositions.