Preface The EC-TEL Doctoral Consortium is part of the EC-TEL since its beginning in 2005. The Doctoral Consortium is part of the doctoral program of the European Association of Technology Enhanced Learning (EATEL). Besides the Doctoral Consortium this program comprises the JTEL Summer School for doctoral candidates. Together, these two events have been shaping and enriching the experiences of many young researchers in their PhD journey and building a community that focuses on and solves the transdisciplinary challenges of our field. This volume contains papers presented at Doctoral Consortium of the Sixteenth European Conference on Technology Enhanced Learning (EC-TEL 2021) held on September 20–21, 2021 in Bolzano, Italy, as a fully online event. There were 20 applications, of which 15 resulted in full paper submissions. Each of the 15 papers have been reviewed by three doctoral consortium committee members. All 15 submissions were found eligible for presentation at the doctoral consortium. The papers in this volume completed the full reflection cycle that is characteristic for the EC-TEL Doctoral Consortium. The EC-TEL Doctoral Consortium is designed as a training event for PhD candidates that seeks to improve the quality of their research. This starts with expressing the own research project and with identifying the limitations and challenges of the present stage. These initial submissions were reviewed by the program committee of senior members of the community. In order to strengthen the learning experience, every doctoral candidate who participated in the event had to review one other submission and raise questions. Together the reviews provide the foundation for the presentations at the Doctoral Consortium, which were then discussed and challenged by the board of experts. Besides paper presentation, the doctoral consortium included a keynote, a social interaction session, mentoring session, and short workshops. After the Doctoral Consortium all participants had the opportunity to present their work as a poster at the main conference, which creates a unique opportunity to engage into discussions with the wider research community. All papers included into these proceedings have been reworked to address the comments of the reviewers and the participants of the event. The submissions to this year's doctoral consortium show the continued relevance for PhD candidates to get qualitative feedback on their projects beyond the level of research papers. Receiving submissions from seven countries across Europe, the EC-TEL Doctoral Consortium shows its international relevance. The variety of topics with both technological and educational focus represented at the doctoral consortium once again highlight the highly multidisciplinary nature of the TEL field. This is complemented by EATEL's activities for building the doctoral community including the series of webinars organized by the DETEL EU project. 31 December 2021 Mikhail Fominykh