Practice-based research (PBR) has emerged as a valuable alternative to traditional scientific methods by generating knowledge through practice and enhancing the relevance of research to practitioners. However, knowledge about PBR has largely been developed within disciplinary silos, leading to its limited cross-disciplinary understanding. This paper addresses this gap by analysing 116 PBR studies in Educational Research and Theatre, two fields with very active but separately analysed PBR traditions. Our analysis produces a framework that categorises PBR into four distinct types based on key dimensions: the 'Aim of research' and the 'Model of practice involvement'. The framework reveals discipline-specific patterns, including divergent tendencies in how PBR is utilised across these fields: in Educational Research, PBR is often employed to improve professional practice, whereas in Theatre, it is central to exploring and theorising practice itself. The proposed framework holds potential for broader applicability across other fields, contributing to a more cohesive understanding of PBR as a versatile research strategy.