Large language models hold great promise for transforming K-12 education, but there is an urgent need for systematic evaluation of their core educational capabilities. Existing benchmarks often overlook educational goal cognition and overemphasize answer accuracy, thereby failing to capture deeper subject-level knowledge ability and problem-solving ability. To address this gap, we introduce K-12EduBench: a benchmark for evaluating LLMs’ subject-level knowledge ability, subject-specific problem-solving ability, and educational goal cognition ability in K-12 education. K-12EduBench comprises four components: (1) a dataset of 2,640 objective and 619 subjective questions across nine subjects, annotated with answers, problem-solving processes, and cognitive-level labels; (2) nine Item Response Theory (IRT) models for estimating subject-level knowledge ability; (3) evaluation methods and metrics for assessing multi-step problem-solving ability; and (4) prompts and scoring rubrics for measuring alignment with target cognitive levels. Experiments on advanced LLMs show that education-optimized models consistently outperform general-purpose ones across all three abilities, while under-scaled models lag substantially. We observe a strong positive correlation between subject-level knowledge ability and subject-specific problem-solving ability. Despite gains in educational goal cognition ability, current models—even those tailored for education—still fall short of real-world instructional needs.

Cognitive diagnosis is a fundamental task in intelligent education, aiming to measure students' proficiency on knowledge concepts based on practice data. Traditional methods utilize a broadly-defined latent trait θ to represent knowledge proficiency with some cognitive factors like skill or ability. However, existing methods simplify this to a narrowly-defined latent trait θ, which focuses only on knowledge or treats these cognitive factors as implicit features inferred from data. They fail to explicitly model these cognitive factors, resulting in limited performance and interpretability. To this end, we revisit essence of cognition in Educational Psychology Theory and propose a novel Cognition-aware Cognitive Diagnosis (CCD) model, where we first introduce the Cognition factor as a bridge into the long-standing three-basic-factors (Student, Exercise, Knowledge concept) paradigm. CCD has two main parts: cognition representations and a two-stage diagnostic process. In the first part, we explicitly model cognitive process (CP) dimensions from Bloom's Taxonomy of Educational Objectives, leading to two innovative concepts proposed: the student's Subjective Cognitive Ability (SCA) and the exercise's Objective Cognitive Attribute (OCA), derived by regulating the CP through S-K and E-K interactions, respectively. Then, the SCA and OCA are formed into a new cognition-aware latent trait θ. In the second part, we employ a basic interaction function and a slip and guess influence function, inputting our new θ, a continuous Q-matrix (generated by a siamese PLMs), and other features to obtain the ideal result, followed by feeding it into the slip and guess influence function to obtain the actual result. Extensive experiments on real-world datasets demonstrates the superior effectiveness and good interpretability.

With the rapid evolution of multimedia technologies and its widespread integration into education, adaptive multimedia learning has gained significant prominence. Cognitive diagnosis (CD) is pivotal in this domain, as it models students' cognitive states using practice data captured by multimedia learning applications. However, existing methods often simplify these states to mere proficiency on knowledge concepts. Constructivism in education emphasizes learning as a continuous cognitive development process, during which students' cognitive states become increasingly complex, involving not only their construction of concepts but also their construction of relations between concepts that have long been overlooked. To this end, we propose the Hierarchical Disentanglement of Cognitive States for Enhanced Cognitive Diagnosis (HDCD). Inspired by the Structure of Observed Learning Outcomes (SOLO) taxonomy, which categorizes cognitive development into core hierarchical levels (Multistructural, Relational, Extended Abstract), we introduce a hierarchical disentanglement strategy to define cognitive states aligned with each SOLO level: Intra-Concept Cognitive States, Relational Cognitive States, and Extended Cognitive States. Specifically, (i) At the multistructural level, intra-concept cognitive states are sampled from student's personalized cognitive distribution, representing the construction of individual concepts. (ii) At the relational level, inter-concept cognitive states are first sampled to represent the construction of relations between concepts. We then employ a hypergraph transformation to collaboratively update both intra-concept and inter-concept cognitive states, forming relational cognitive states. Considering that students' self-constructed knowledge systems involve multiple types of inter-concept relations, relational cognitive states are implemented under both undirected and directed relation views in this work, and then fed into local diagnostic functions, respectively. (iii) At the extended abstract level, outputs from the local diagnostic functions are fused using multi-view attention mechanisms, resulting in extended cognitive states, which integrate information from multiple relational views, are then fed into a global diagnostic function for final prediction. Extensive experiments on real-world datasets demonstrate the superior performance and interpretability of our HDCD.

The knowledge concept recommendation in Massive Open Online Courses (MOOCs) is a significant issue that has garnered widespread attention. Existing methods primarily rely on the explicit relations between users and knowledge concepts on the MOOC platforms for recommendation. However, there are numerous implicit relations (e.g., shared interests or same knowledge levels between users) generated within the users' learning activities on the MOOC platforms. Existing methods fail to consider these implicit relations, and these relations themselves are difficult to learn and represent, causing poor performance in knowledge concept recommendation and an inability to meet users' personalized needs. To address this issue, we propose a novel framework based on contrastive learning, which can represent and balance the explicit and implicit relations for knowledge concept recommendation in MOOCs (CL-KCRec). Specifically, we first construct a MOOCs heterogeneous information network (HIN) by modeling the data from the MOOC platforms. Then, we utilize a relation-updated graph convolutional network and stacked multi-channel graph neural network to represent the explicit and implicit relations in the HIN, respectively. Considering that the quantity of explicit relations is relatively fewer compared to implicit relations in MOOCs, we propose a contrastive learning with prototypical graph to enhance the representations of both relations to capture their fruitful inherent relational knowledge, which can guide the propagation of students' preferences within the HIN. Based on these enhanced representations, to ensure the balanced contribution of both towards the final recommendation, we propose a dual-head attention mechanism for balanced fusion. Experimental results demonstrate that CL-KCRec outperforms several state-of-the-art baselines on real-world datasets in terms of HR, NDCG and MRR.