Measuring Validity in LLM-based Resume Screening

TL;DR

This paper introduces a framework for evaluating the validity of LLM-based resume screening systems by constructing a large, ground-truth dataset, revealing inconsistencies and biases in model decisions.

Contribution

It presents a novel dataset and methodology for systematically measuring the validity of LLM resume screening, addressing the lack of ground truth in current evaluations.

Findings

Many LLMs struggle to consistently identify more qualified candidates.

Models often do not abstain reliably when candidates are equally qualified.

Biases exist in demographic group selection rates, sometimes favoring marginalized groups.

Abstract

Resume screening is perceived as a particularly suitable task for LLMs given their ability to analyze natural language; thus many entities rely on general purpose LLMs without further adapting them to the task. While researchers have shown that some LLMs are biased in their selection rates of different demographics, studies measuring the validity of LLM decisions are limited. One of the difficulties in externally measuring validity stems from lack of access to a large corpus of resumes for whom the ground truth in their ranking is known and that has not already been used for LLM training. In this work, we overcome this challenge by systematically constructing a large dataset of resumes tailored to particular jobs that are directly comparable, with a known ground truth of superiority. We then use the constructed dataset to measure the validity of ranking decisions made by various LLMs, finding that many models are unable to consistently select the resumes describing more qualified candidates. Furthermore, when measuring the validity of decisions, we find that models do not reliably abstain when ranking equally-qualified candidates, and select candidates from different demographic groups at different rates, occasionally prioritizing historically-marginalized candidates. Our proposed framework provides a principled approach to audit LLM resume screeners in the absence of ground truth, offering a crucial tool to independent auditors and developers to ensure the validity of these systems as they are deployed.