Beyond the dashboard: Architecture, maturity, and performance outcomes in operational building digital twins — A scoping review

The concept of a digital twin has been widely promoted as a means of achieving smarter building operations in recent years. However, much of the published literature bearing this label merely involves static BIM geometries, isolated energy simulations, or hypothetical building designs that are not linked to a real operating building. This review was inspired by a simple question: how many studies that purport to apply digital twins in practice actually do so in an operational sense? To answer this question, 2301 records were extracted from Scopus, Web of Science, and IEEE Xplore, and subsequently filtered using a three-stage screening protocol based on document type, abstract content, and evidence of real-time data connectivity, physical sensor deployment, and confirmed operational phase application. Only 37 studies passed all three stages of the review process. These were examined across four dimensions (architecture, functionality, maturity, and validation), yielding the Operational Digital Twin Maturity Matrix. To the best of the authors' knowledge, this is the first empirically derived framework cross-tabulating architectural configurations and functional capabilities against operational maturity levels across live building deployments. All 37 studies feature real-time data exchange, IoT connectivity, and live instrumentation (100%), and 97.3% integrate BIM. Functionally, IEQ monitoring dominates (73.0%), followed by energy optimisation (40.5%) and asset management (35.1%). Nearly half of all implementations (48.6%) remain at the descriptive level, providing real-time monitoring and visualisation dashboards, whereas only 24.3% reach the prescriptive level, where the twin actively drives control decisions. More significantly, only 27% of the included studies report quantified performance outcomes, although prescriptive studies are four times as likely to do so, with reported outcomes including a 34% electricity cost reduction and a 14.5% reduction in HVAC power consumption. Grounded in 37 verified operational deployments rather than conceptual frameworks, the matrix offers a realistic and empirically justified reference point for researchers, developers, and facility managers navigating digital twin investment decisions.