In this paper, we discuss the benefits and challenges of shared tasks as a teaching method. A shared task is a scientific event and a friendly competition to solve a research problem, the task. In terms of linking research and teaching, shared-task-based tutorials fulfill several faculty desires: they leverage students' interdisciplinary and heterogeneous skills, foster teamwork, and engage them in creative work that has the potential to produce original research contributions. Based on ten information retrieval (IR) courses at two universities since 2019 with shared tasks as tutorials, we derive a domain-neutral process model to capture the respective tutorial structure. Meanwhile, our teaching method has been adopted by other universities in IR courses, but also in other areas of AI such as natural language processing and robotics.

We present an approach to identify argumentative questions among web search queries. Argumentative questions ask for reasons to support a certain stance on a controversial topic, such as ''Should marijuana be legalized?'' Controversial topics entail opposing stances, and hence can be supported or opposed by various arguments. Argumentative questions pose a challenge for search engines since they should be answered with both pro and con arguments in order to not bias a user toward a certain stance.

In this paper, we analyze comparative questions and answers. At least 3%~of the questions submitted to search engines are comparative; ranging from simple facts like "Did Messi or Ronaldo score more goals in 2021?'' to life-changing and probably highly subjective questions like "Is it better to move abroad or stay?''. Ideally, answers to subjective comparative questions would reflect diverse opinions so that the asker can come to a well-informed decision. To better understand the information needs behind comparative questions, we develop approaches to extract the mentioned comparison objects and aspects. As a first step to answer comparative questions, we develop an approach that detects the stances of potential result nuggets (i.e., text passages containing the comparison objects). Our approaches are trained and evaluated on a set of 31,000~English questions from existing datasets that we label as comparative or not. In the 3,500~comparative questions, we label the comparison objects, aspects, and predicates. For 950~questions, we collect answers from online forums and label the stance towards the comparison objects. In the experiments, our approaches recall~71% of the comparative questions with a perfect precision of~1.0, recall~92% of subjective comparative questions with a precision of~0.98, and identify the comparison objects and aspects with an F1 of~0.93 and~0.80, respectively. The stance detector fine-tuned on pairs of objects and answers achieves an accuracy of~0.63.

Yamen Ajjour, Milad Alshomary, Henning Wachsmuth, Benno Stein. Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP). 2019.

Future search engines are expected to deliver pro and con arguments in response to queries on controversial topics.While argument mining is now in the focus of research, the question of how to retrieve the relevant arguments remains open.This paper proposes a radical model to assess relevance objectively at web scale: the relevance of an argument's conclusion is decided by what other arguments reuse it as a premise.We build an argument graph for this model that we analyze with a recursive weighting scheme, adapting key ideas of PageRank.In experiments on a large ground-truth argument graph, the resulting relevance scores correlate with human average judgments.We outline what natural language challenges must be faced at web scale in order to stepwise bring argument relevance to web search engines.