As you're interested in finding the research trend or topics in Educational Data Mining, you are suggested to read some of the important research articles, particularly review papers. Due to this, I have made a list of some selected papers which might be useful for your research. To check out them, go to the following links:
[1] Baker, R. S., & Yacef, K. (2009). The state of educational data mining in 2009: A review and future visions. JEDM| Journal of Educational Data Mining, 1(1), 3-17.
[2] Romero, C., & Ventura, S. (2010). Educational data mining: a review of the state of the art. IEEE Transactions on Systems, Man, and Cybernetics, Part C (Applications and Reviews), 40(6), 601-618.
[3] Papamitsiou, Z., & Economides, A. A. (2014). Learning analytics and educational data mining in practice: A systematic literature review of empirical evidence. Journal of Educational Technology & Society, 17(4), 49.
[4] Slater, S., Joksimović, S., Kovanovic, V., Baker, R. S., & Gasevic, D. (2017). Tools for educational data mining: A review. Journal of Educational and Behavioral Statistics, 42(1), 85-106.
[5] Dutt, A., Ismail, M. A., & Herawan, T. (2017). A systematic review on educational data mining. IEEE Access, 5, 15991-16005.
[6] Angeli, C., Howard, S. K., Ma, J., Yang, J., & Kirschner, P. A. (2017). Data mining in educational technology classroom research: Can it make a contribution?. Computers & Education, 113, 226-242.
[7] Bakhshinategh, B., Zaiane, O. R., ElAtia, S., & Ipperciel, D. (2018). Educational data mining applications and tasks: A survey of the last 10 years. Education and Information Technologies, 23(1), 537-553.
I suggest you to check the last papers published in the proceedings of EDM (International Conference on Educational Data Mining): http://educationaldatamining.org/EDM2017/proceedings-full/
This might be a good source for "hot topics" in the field
Well, as Eduardo a Philippe said, the most important think is reading a lot about the topic. Usually the most recent publications can give you a clue about what are the hottest topics. I specially recommend you the proceedings of the EDM conference that you can find at the EDM organization website (http://educationaldatamining.org/conferences/).
If your aim is knowing the hot topics in data mining , I can refer to most of topics such as attached file, as I work and research on data mining, I can suggest variety of topics like classification, clustering, spectral clustering, semi-supervised learning and ..., I prepare the attached file in order to understanding the best topics.
At the web page of the society FORlearning analytics research (SOLAR) you can find interesting topics, besides the official Journal of the society offers high quality papers about Educational Data Mining.
On the other hand, I would like to mention a specific possible topic: the relationship between data mining, semantization, and "semantical mining" (I am not sure, but probably, I am inventing this term just know, but, anyway, it`s irrelevant, I am sure you understood). The idea is: by means of data mining, take place the discovery of new, not explicit relations. These relations can be then used as a way to develop, enrich, ontologies, which are the basis of semantization of the studied domain. This domain, with new, reveled semantic relations, can be, again, "semantically mined", but now the discovery gives a more detailed characterization.
The key problem here to put all these together is to find "a priori" a suitable way to structure the resulting discovered data/knowledge.
Based on my experience in field of education, you can conduct a research to classify student learning based on behave and environment and many other factors. The finding can help institutes, organization and government to manage better their resource specially for those who have limit resource or community-based education (CBE) in past conflict country.
Online education is also a grooming research area .Online Education is facing many problems for example students are not completing the courses i.e. the completion rate is very low.SO efforts can be taken to increase the course completion rate.
As you're interested in finding the research trend or topics in Educational Data Mining, you are suggested to read some of the important research articles, particularly review papers. Due to this, I have made a list of some selected papers which might be useful for your research. To check out them, go to the following links:
[1] Baker, R. S., & Yacef, K. (2009). The state of educational data mining in 2009: A review and future visions. JEDM| Journal of Educational Data Mining, 1(1), 3-17.
[2] Romero, C., & Ventura, S. (2010). Educational data mining: a review of the state of the art. IEEE Transactions on Systems, Man, and Cybernetics, Part C (Applications and Reviews), 40(6), 601-618.
[3] Papamitsiou, Z., & Economides, A. A. (2014). Learning analytics and educational data mining in practice: A systematic literature review of empirical evidence. Journal of Educational Technology & Society, 17(4), 49.
[4] Slater, S., Joksimović, S., Kovanovic, V., Baker, R. S., & Gasevic, D. (2017). Tools for educational data mining: A review. Journal of Educational and Behavioral Statistics, 42(1), 85-106.
[5] Dutt, A., Ismail, M. A., & Herawan, T. (2017). A systematic review on educational data mining. IEEE Access, 5, 15991-16005.
[6] Angeli, C., Howard, S. K., Ma, J., Yang, J., & Kirschner, P. A. (2017). Data mining in educational technology classroom research: Can it make a contribution?. Computers & Education, 113, 226-242.
[7] Bakhshinategh, B., Zaiane, O. R., ElAtia, S., & Ipperciel, D. (2018). Educational data mining applications and tasks: A survey of the last 10 years. Education and Information Technologies, 23(1), 537-553.
C. Romero, S. Ventura and E. García, "Data mining in course management systems: Moodle case study and tutorial", Computers & Education, vol. 51, no. 1, pp. 368-384, 2008.
It is a very useful article......
It introduces both theoretically and practically to all users interested in Educational Data Mining
I believe that topics related to deep learning and use of ensemble of different mining methods in search of better results are relevant research topics in the area. The events related in the other answers are good sources.