Figure 1.

Transfer learning as implemented in this study. In part 1, a prediction model neural network (such as Artificial Intelligence Sepsis Expert) is initialized with random weights and is trained with data from the development site. In part 2, starting with a pretrained model from the development site, the model weights are fine-tuned (or retrained) with a relatively small amount of data from the validation site before application to the validation cohort. This procedure is called transfer learning.