Model validation is the process of assessing the accuracy and reliability of a mathematical or computational model by comparing its predictions to real-world data. This involves testing the model's assumptions, parameters, and predictions against observed outcomes to determine if the model is capable of accurately representing the phenomenon being studied. Validation is an essential step in the development and use of models in various scientific disciplines, such as economics, engineering, climate science, and epidemiology, to ensure that the model is robust and trustworthy for decision-making purposes.