Definitions of transdisciplinarity vary. It is clear that this is research that spans across different disciplines and knowledge domains, and may create interaction between these different disciplines, and these disciplines may opt for a clear integration or collaboration. In addition, these can have common goals and aims, or collaborate on the creation of joint solutions. Extra-academic knowledge is often seen as important in transdisciplinary research, and may serve as the main distinguishing factor compared to interdisciplinarity, although there is no consensus about this.