A decision rule is like a list of rules that help you make decisions. It's like a set of steps that you can follow when you need to make a choice. For example, if you are deciding which book to read, you might have a decision rule that says: "First, look for books you like. Second, choose the book that has the most interesting plot. Third, double check that it has age-appropriate content." Following each step will help you make the best decision for you.