AI-written cover letters were ranked by which model wrote them, not by the candidate
AspireAI community · arXiv (cs.CY, cs.AI, cs.MA)
With applicants using LLMs to write cover letters and employers using LLMs to screen them, this audit asks whether the choice of writer model changes hiring outcomes independently of candidate quality. Eleven writer agents were paired with nine API-hosted evaluator agents across ten job descriptions and fifty candidates per job. Three findings stand out: locally hosted writer models are systematically disadvantaged regardless of licence, evaluators show self-preference bias toward their own outputs, and in the most adverse pairing about two of twenty-five qualified candidates are filtered out purely because of model mismatch. The authors trace the pattern to stylistic cues that evaluators reward or penalise almost unanimously, and find little evidence of a residual writer fingerprint once those features are accounted for. They report scenario-level differences because the personas vary on several attributes at once, so the age and expertise effects are not isolated.
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Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.