A typology of explanations to support Explainability-by-Design

As automated decision-making permeates almost all aspects of everyday life, capabilities to generate meaningful explanations for various stakeholders (i.e., decision-makers, addressees of decisions including individuals, auditors, and regulators) should be carefully deployed. This article presents a typology of explanations intended to support the first pillar of an explainability-by-design strategy. Its production has been achieved by pursuing a responsible innovation approach and introducing a new persona within the research and innovation process, i.e., a legal engineer, whose role is to work at the interface of two teams, the compliance and the engineering teams, and to oversee the process of requirement elicitation, which is often opinionated and narrowing. Once explanation requirements have been derived from applicable regulatory requirements, compliance rules, or business policies, they have been mapped to the dimensions of the typology to produce fine-grained explanation requirements, forming computable building blocks that can then be translated into system requirements during the technical design phase. The typology has been co-created with industry partners operating in two sectors: finance and education. Two pilot studies have thus been conducted to test both the feasibility of the generation and computation of explanations on the basis of the typology and the usefulness of the outputs in the light of the state-of-the-art. The typology comprises nine hierarchical dimensions. It can be leveraged to operate a stand-alone classifier of explanations that acts as detective controls within a broader partially automated compliance strategy. A machine-readable format of the typology is provided in the form of a light ontology.