Architecture decision making is a central activity in software engineering processes, yet it is often treated implicitly or reduced to isolated technical choices (van Heesch et al., 2012; Kruchten et al., 2019). This paper proposes an Architecture Decision Model (ADM) that makes architectural decision logic explicit as a structured, repeatable process, addressing a recurring need for decision transparency in evolving software-intensive systems (Bosch, 2014; Hilliard et al., 2020). The model supports process tailoring by allowing decision concerns, decision criteria, and decision artifacts to be systematically adapted to project-specific contexts, reflecting empirical observations that architecture effort must be proportional to project risk and complexity (Waterman et al., 2015). Rather than prescribing a fixed set of architectural views or documents, the model guides practitioners in determining what architectural knowledge should be produced, when, and for whom, complementing existing view-based architecture description standards (ISO/IEC/IEEE 42010, 2011). The ADM is designed to integrate with the software lifecycle and organizational governance mechanisms, enabling traceability between project characteristics, architectural concerns, and decision outcomes across system evolution (Bosch, 2014; Lago et al., 2015). A case study illustrates how the model supports consistent architectural decision making over time while accommodating changing project constraints.