Within the nuclear industry there is an extensive need for evaluation of the safety of the plant. In such evaluations there is one phenomenon requiring some particular treatment, namely common cause failure (CCF). This involves the occurrences of components failing dependently, meaning failures that can overcome the applied redundancy or diversity. The impact of CCF is relatively large, but unfortunately the process of CCF analysis is complicated by the complex nature of CCF events and a very sparse availability of CCF data. Today, there are a number of methods for CCF analysis available with different characteristics, especially concerning their qualitative and quantitative features. The most common working procedure for CCF treatment is to divide the analysis in a qualitative and a quantitative part, but unfortunately the development of tools for the qualitative part has to a certain extent got behindhand. This subject is further explored in a comparative study focused on two totally different approaches for CCF analysis, the impact vector method and the unified partial method. Based on insights from this study an integrated impact vector and ‘Relations of Defences, Root causes and Coupling factors’ (RDRC) methodology is suggested to be further explored for progress towards a methodology incorporating both qualitative and quantitative aspects.