Selective Mixup for Debiasing Question Selection in Computerized Adaptive Testing

Fuente: arXiv
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Main Authors: Tian, Mi, Zhang, Kun, Liu, Fei, Li, Jinglong, Liao, Yuxin, Bai, Chenxi, Tan, Zhengtao, Wu, Le, Hong, Richang
Format: Preprint
Published: 2025
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author Tian, Mi
Zhang, Kun
Liu, Fei
Li, Jinglong
Liao, Yuxin
Bai, Chenxi
Tan, Zhengtao
Wu, Le
Hong, Richang
author_facet Tian, Mi
Zhang, Kun
Liu, Fei
Li, Jinglong
Liao, Yuxin
Bai, Chenxi
Tan, Zhengtao
Wu, Le
Hong, Richang
contents Computerized Adaptive Testing (CAT) is a widely used technology for evaluating learners' proficiency in online education platforms. By leveraging prior estimates of proficiency to select questions and updating the estimates iteratively based on responses, CAT enables personalized learner modeling and has attracted substantial attention. Despite this progress, most existing works focus primarily on improving diagnostic accuracy, while overlooking the selection bias inherent in the adaptive process. Selection Bias arises because the question selection is strongly influenced by the estimated proficiency, such as assigning easier questions to learners with lower proficiency and harder ones to learners with higher proficiency. Since the selection depends on prior estimation, this bias propagates into the diagnosis model, which is further amplified during iterative updates, leading to misalignment and biased predictions. Moreover, the imbalanced nature of learners' historical interactions often exacerbates the bias in diagnosis models. To address this issue, we propose a debiasing framework consisting of two key modules: Cross-Attribute Examinee Retrieval and Selective Mixup-based Regularization. First, we retrieve balanced examinees with relatively even distributions of correct and incorrect responses and use them as neutral references for biased examinees. Then, mixup is applied between each biased examinee and its matched balanced counterpart under label consistency. This augmentation enriches the diversity of bias-conflicting samples and smooths selection boundaries. Finally, extensive experiments on two benchmark datasets with multiple advanced diagnosis models demonstrate that our method substantially improves both the generalization ability and fairness of question selection in CAT.
format Preprint
id arxiv_https___arxiv_org_abs_2511_15241
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Selective Mixup for Debiasing Question Selection in Computerized Adaptive Testing
Tian, Mi
Zhang, Kun
Liu, Fei
Li, Jinglong
Liao, Yuxin
Bai, Chenxi
Tan, Zhengtao
Wu, Le
Hong, Richang
Information Retrieval
Computerized Adaptive Testing (CAT) is a widely used technology for evaluating learners' proficiency in online education platforms. By leveraging prior estimates of proficiency to select questions and updating the estimates iteratively based on responses, CAT enables personalized learner modeling and has attracted substantial attention. Despite this progress, most existing works focus primarily on improving diagnostic accuracy, while overlooking the selection bias inherent in the adaptive process. Selection Bias arises because the question selection is strongly influenced by the estimated proficiency, such as assigning easier questions to learners with lower proficiency and harder ones to learners with higher proficiency. Since the selection depends on prior estimation, this bias propagates into the diagnosis model, which is further amplified during iterative updates, leading to misalignment and biased predictions. Moreover, the imbalanced nature of learners' historical interactions often exacerbates the bias in diagnosis models. To address this issue, we propose a debiasing framework consisting of two key modules: Cross-Attribute Examinee Retrieval and Selective Mixup-based Regularization. First, we retrieve balanced examinees with relatively even distributions of correct and incorrect responses and use them as neutral references for biased examinees. Then, mixup is applied between each biased examinee and its matched balanced counterpart under label consistency. This augmentation enriches the diversity of bias-conflicting samples and smooths selection boundaries. Finally, extensive experiments on two benchmark datasets with multiple advanced diagnosis models demonstrate that our method substantially improves both the generalization ability and fairness of question selection in CAT.
title Selective Mixup for Debiasing Question Selection in Computerized Adaptive Testing
topic Information Retrieval
url https://arxiv.org/abs/2511.15241