Screen ID (definition)

Each screen has a unique identifier generated mathematically from the number, position, and length of the fields. If you know that the fields will always be in the same place and of the same length, you can rely on this value being the same each time the screen is loaded. You can use screen ID even if some of the values within fields are going to change. For example, if there is a time stamp located in the top left corner, and that field is always the same length, the screen will keep it's unique ID even if the time of day is different.