Engineering disciplines are paying increasing attention to transdisciplinary (TD) working. The terminology of single, multidisciplinary, interdisciplinary and transdisciplinary lacks clarity. Consequently, there is currently no consensus on what defines a TD research approach. This makes it difficult to implement and measure the impact of TD and TD working. Clear definition of the approach and understanding of where TD is most applicable is needed because the education of tomorrow’s engineers can only be realised if researchers build upon coherent theoretical frameworks. This paper draws on theory to define TD and then aims to reduce confusion and instill clarity by identifying when TD as a research approach should or should not be used. This is achieved by answering the research question: when might it be beneficial to take a TD rather than single, multi or interdisciplinary research approach? Survey responses from twenty-eight authors (50%) who presented papers at the 28th ISTE International Conference on Transdisciplinary Engineering (TE2021) were qualitatively analysed. Findings show institutional barriers to TD adoption may prevent the benefits of TD engineering research from being realised. Rather than the research approach itself, it is the environment in which we do our research, one which is decided long before our work begins, that will determine if any meaningful benefits from TD are realised.