Evaluating Transparency in the Development of Artificial Intelligence Systems: A Systematic Literature Review

Transparency is increasingly recognised as a cornerstone of trustworthy artificial intelligence (AI), yet its operationalisation remains fragmented and underdeveloped. Existing methods often rely on qualitative checklists or domain-specific case studies, limiting comparability, reproducibility, and regulatory alignment. This paper presents a Systematic Literature Review (SLR) of 28 peer-reviewed studies that explicitly propose or apply methods for evaluating transparency in AI systems (2019-July 2025). The review identifies recurring themes such as traceability, explainability, and communication, and classifies evaluation approaches by metric type and calculation type. Empirically, checklist-based instruments are the most frequent evaluation form (9/28, 32%), followed by scenario-based qualitative assessments (5/28, 18%). Most (9/28, 32%) research on AI applications occurs in healthcare; references to legal or ethical frameworks appear in 19/28 studies (67%), although traceable mappings to specific obligations are rare. The results of the quality assessment highlight strengths in methodological clarity, but reveal persistent gaps in benchmarking, stakeholder inclusion, and lifecycle integration. Based on these findings, this study informs the adaptation of the Z-Inspection® process within the context of AI development projects and motivates a Transparency Artefact Registry (TAR), a structured, metadata-based mechanism for capturing and reusing transparency artefacts across system lifecycles. By embedding transparency evaluation into AI development workflows, the proposed approach seeks to provide verifiable, repeatable, and regulation-aligned practices for assessing transparency in complex AI systems.