Before revision: Validity is important because it can help determine what types of tests to use, and help to ensure researchers are using methods that are not only ethical and cost-effective, but also a method that truly measures the idea or constructs in question.
After revision: Validity is important because it can help determine what types of tests to use, and help to ensure researchers are using methods that are not only ethical and cost-effective, but also those that truly measure the ideas or constructs in question.