Fig. 4: Model classification and data flow for digital models—differentiating digital models from digital shadows and human digital twins, in healthcare.
From: A scoping review of human digital twins in healthcare applications and usage patterns

Data flows into a virtual model from a variety of sources, stemming from human subjects or their environment. Some models are parameterized exactly once, while others are dynamically updated in a recurring fashion. In digital twin models, the data flows from the model back into the data-sources (i.e. the subject or physical system is somehow modified based on predictions made by the digital twin) such that the ongoing model parameterization reflects decisions and advice generated by the model.