IELTS is a formal qualification, but it is much more than just a piece of paper. The right score acts as a key that can open the door to a new life. For those who do not achieve their target, the test represents a closed door blocking their way. IELTS has this power because many government bodies and universities rely on it as an accurate measure of English language. A high-level certificate tells the world that you have enough English to successfully study at university, or to work in a highlevel professional capacity. This is why it is so important that the test is valid, fair, and reliable. As we will repeatedly see, it is equally important that the practice materials you use also have these qualities.