The Impact of Data Imbalance on the Explainability of Text Classification Models: A Comparative Analysis with SVM and LSTM
Resumo
This paper investigates the systematic impact of data imbalance and sampling strategies on the explainability of text classification models. By confronting a linear SVM with a LSTM network, we analyze the mathematical consistency of local post-hoc explanations generated by LIME and SHAP, alongside feature relevance and deep attention mechanisms across five datasets. Non-parametric statistical evaluations via Friedman’s test reveal that while SHAP maintains high stability due to its axiomatic foundation, LIME and attention mechanisms exhibit severe structural vulnerabilities. Notably, oversampling text sequences for LSTM triggers localized redundancy, causing attention weights to oscillate erratically and undermining explanation reliability.
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