In this study we evaluate the research performance of the Computer Science departments in United Kingdom. We consider the research activity as a series process with two components, where the first component portrays the research productivity and the second component portrays the impact of the research outcomes of each department. The analysis is based on the data drawn from the Research Excellence Framework 2014 (REF 2014), which is the system for assessing the quality of research in the higher education institutions of United Kingdom. We carry out the assessment by employing the composition approach of Network Data Envelopment Analysis (Network DEA). Also, we encompass a qualitative aspect into the exercise based on the categorization of the publications provided by REF 2014.