The proportion of predictions a model gets correct. Accuracy is context-dependent and often misleading without additional metrics: a model that predicts "no fraud" for every transaction achieves 99% accuracy if fraud occurs in only 1% of cases. Marketing claims citing accuracy should specify the dataset, task, and conditions; high accuracy on benchmarks may mask poor performance on important subgroups.
See: Evaluation (evals); F1 score; Precision; Recall