Emerging scholarship suggests that the EU legal concept of direct discrimination - where a person is given different treatment on grounds of a protected characteristic - may apply to various algorithmic decision-making contexts. This has important implications: unlike indirect discrimination, there is generally no 'objective justification' stage in the direct discrimination framework, which means that the deployment of directly discriminatory algorithms will usually be unlawful per se. In this paper, we focus on the most likely candidate for direct discrimination in the algorithmic context, termed inherent direct discrimination, where a proxy is inextricably linked to a protected characteristic. We draw on computer science literature to suggest that, in the algorithmic context, 'treatment on the grounds of' needs to be understood in terms of two steps: proxy capacity and proxy use. Only where both elements can be made out can direct discrimination be said to be `on grounds of' a protected characteristic. We analyse the legal conditions of our proposed proxy capacity and proxy use tests. Based on this analysis, we discuss technical approaches and metrics that could be developed or applied to identify inherent direct discrimination in algorithmic decision-making.

翻译：新兴学术研究表明，欧盟法律中的直接歧视概念——即因受保护特征而对个人给予不同对待——可能适用于多种算法决策场景。这具有重要影响：与间接歧视不同，直接歧视框架通常不存在"客观合理性抗辩"阶段，这意味着部署直接歧视性算法通常本身即为违法。本文聚焦于算法语境中最可能构成直接歧视的情形，即所谓的固有直接歧视——其中代理变量与受保护特征存在不可分割的关联。我们借鉴计算机科学文献提出，在算法语境中，"因……理由而给予对待"需要从两个维度理解：代理容量与代理使用。仅当这两项要素均能成立时，才能认定直接歧视系"基于"受保护特征。我们分析了所提出的代理容量与代理使用测试的法律要件，并基于此讨论可开发或应用于识别算法决策中固有直接歧视的技术方法与评估指标。