Modern enterprises face the challenge of volatile markets. The multifarious influencing factors particularly include uncertain demand quantities. This means that it is increasingly important for production systems to be able to react quickly. At the same time, it is becoming more and more difficult to adequately depict this specific volume flexibility due to the complexity of the systems involved. Although existing research work has recognised flexibility as a decisive competitive factor for production systems, the focus until now has only been on qualitative investigations. Quantitative approaches are only found for specific problems. This paper presents a new approach to depict and analyse the volume flexibility of production systems in consideration of existing definitions and approaches. The resulting paths of investigation serve as approaches for future research projects for a quantitative analysis and optimisation of the volume flexibility of production systems.