The Selenium Page Object Model is based on the programming concepts that a page object class should include all aspects of the page under test, such as the elements on the page, the methods for interacting with those elements, variables, and properties associated with the class. Following that concept, there is no data stored in the page object class. The test classes themselves call methods on the page object instances they are testing, but have no knowledge of the granular elements in the class. Finally, the actual test data is encapsulated outside the test class in a central location. In other words, there is an abstract layer created between the tests and the actual page object classes. This reduces the amount of code being written and allows them to be reused in various testing scenarios, thus following the DRY approaches to programming. From a maintenance point of view, changes to methods and locators are made in limited, central places, reducing the amount of time required to maintain ever-changing applications.