IELTS Speaking Part 2: using the prompts

 An IELTS teacher asked me the following questions:

Is it compulsory for candidates to address all of the prompts on the cue card? What happens if candidates ignore the prompts but speak well about the topic anyway? And what happens if the candidate misunderstands the question and speaks about a different topic?

Here are the answers that I gave the teacher:

I tell my students to use the prompts because they help you to structure your answer. However, it is still possible to get a very high score even if you don't address all of the points e.g. if you speak well about the topic but miss the last point or two. I don't recommend ignoring the points completely, because there's a danger that you'll go off task if you do that.

If you misunderstand the question and give an unrelated answer, I'm afraid you'll get a very low score. The reason is that candidates could memorise a perfect answer if off-topic answers were allowed.