One general way of defining transdisciplinarity could be as interactions between scientists of different disciplines and representatives of different stakeholder groups in order to interlink context specific, but different, insights, interests and values (Agramont et al, 2019).

While there are many other definitions available, the key problem lies in evaluating the result of a transdisciplinary study, mainly because it is a newly emerged discipline and there are no universally recognised criteria for evaluation. Carew and Wickson (2010) present a tool called “Transdisciplinary Wheel” (TDW) to assist researchers engaged in so-called 'messy-problems' such as homelessness, using a transdisciplinary approach. The wheel suggests interrelation between the context, process and product of the research and provides a flexible support to visualise the research process.

According to a report (The group of specialists, 2008) published by the Council of Europe, vulnerable groups cannot be defined without specific contextual and historical elements, they do however include immigrants, unemployed, victims of wars and disasters, frail and elderly etc., and for them, homelessness presents one of the major housing problems.

In cases where certain vulnerable groups have lacked the capacity to organise themselves in seeking their rights or improving their position, the importance of civil society organisations has been significant. When public institutions could not have addressed problems and meet certain needs for vulnerable groups, the service is usually catered by different stakeholders, among them advocacy civil society organisations (Bežovan et al., 2016), and they could bring great value for the transdisciplinary research approach.

One real-life example is the project currently being conducted in Los Angeles, USA, where a transdisciplinary approach is implemented to find faster and easier solutions for homeless people and integrate them across the system (Lipinski, 2020). Homeless people in Los Angeles, along with the lack of shelter and a safe place to conduct basic human activities, face racial inequality. Stakeholders such as community-based organisations, policy experts, psychiatrists, biobehavioral scientists and academia, together with ad-hoc groups of people experiencing homelesness, apply computer and social work science to implement artificial intelligence and machine learning to find ways that may help homeless people. 

This example explains the definition of a transdisciplinary approach by showing the collaboration of different academic and non-academic experts that innovatively employed their expertise from computer and social science for the benefit of social service in real life application.

References:

Agramont, A., Craps, M., Balderrama, M. and Huysmans, M. (2019) “Transdisciplinary Learning Communities to Involve Vulnerable Social Groups in Solving Complex Water-Related Problems in Bolivia”, Water 11(2), DOI: 10.3390/w11020385

Bežovan, G., Matančević, J., i Baturina, D. (2016). “Socijalne inovacije kao doprinos jačanju socijalne kohezije i ublažavanju socijalne krize u europskim urbanim socijalnim programima” (en. Social Innovations as a Contribution to Strengthening Social Cohesion and Mitigating Social Crisis in European Urban Social Programmes), Journal for Social policy, 23(1), page 61-80. https://doi.org/10.3935/rsp.v23i1.1279

Carew, A. L. and Wickson, F. (2010) “The TD Wheel: A heuristic to shape, support and evaluate transdisciplinary research”, Futures 42 (2010) 1146–1155

Lipinski, L. (2020) “Transdisciplinary research team led by USC professors will help Los Angeles reduce bias and disparity in homelessness services”, USC Suzanne Dworak-Peck, School of Social Work, online resource, published 23.06.2020, accessed on 13.7.2021,https://dworakpeck.usc.edu/news/transdisciplinary-research-team-led-usc-professors-will-help-los-angeles-reduce-bias-and

The Group of Specialists on Housing Policies for Social Cohesion (2008) “Housing policy and vulnerable  groups”, Council of Europe Publishing, ISBN 978-92-871-6300-4

Additional read on the subject of transdisciplinarity

Barry, A. and Born, G. (2013) “Interdisciplinarity; reconfigurations of the social and natural sciences”, Routledge, 2 Park Square, Milton Park, Abingdon, Oxon OX14 4RN

Barth, M., Lang, D.J. and Michelsen, G. (2019) “Transdisciplinary learning to foster sustainable development. Institutionalizing co-engaged South-North collaboration”, GAIA 28/4 (2019): 382 –385.

Becker, E. (2004/Rev.2006), “PROBLEM TRANSFORMATIONS IN TRANSDISCIPLINARY RESEARCH”, in Unity of Knowledge in Transdisciplinary Research for Sustainability, [Ed.  Gertrude  Hirsch Hadorn], in Encyclopedia of Life Support Systems (EOLSS), Developed under the Auspices of the UNESCO,Eolss Publishers, Oxford ,UK.

Bergman, M., Schramm, E., Brohmann, B. and Rehaag, R. (2005) “Quality Criteria of Transdisciplinary Research: A Guide for the Formative Evaluation of Research Projects” Institut für sozial-ökologische Forschung (ISOE)Editor: Institut für sozial-ökologische Forschung (ISOE), ISBN: 0947-6083

Lang, D.J., Wiek, A., Bergmann, M. et al. (2012) “Transdisciplinary research in sustainability science: practice, principles, and challenges”, Sustain Sci 7, 25–43 (2012). https://doi.org/10.1007/s11625-011-0149-x

Scholz, R.W., Lang, D.J., Wiek, A., Walter, A.I. and Stauffacher, M. (2006), "Transdisciplinary case studies as a means of sustainability learning: Historical framework and theory", International Journal of Sustainability in Higher Education, Vol. 7 No. 3, pp. 226-251. https://doi.org/10.1108/14676370610677829