Hints and Tips On Using PI in Lectures
Prepare students in advance
Be sure to inform students about what you will be doing right at the start of the first lecture, before asking them any questions. Explain to them that you will be occaisonally stopping to ask a question that everyone will have to answer and explain how this will be done (for example, by holding up flash cards or using clickers). Let them know that the aim is to make the lectures more interactive and interesting and to get them thinking a bit. Reassure them that they are not being tested or assessed. Mention some of the advantages of this way of teaching; for example that it provides some immediate and useful feedback to both the lecturer and the students themselves on how well they are following the material.
Don't try to do too much. Use your own judgement, but 3-5 questions is usually enough for a one hour lecture. Even just 1 or 2 questions can be beneficial.
The questions you use should be properly integrated into the lecture you actually give. That is, they should be relevant to the topic you've just been talking about, make use the same terminology and so on.
There's nothing wrong with starting off with an easy question that you're pretty sure most students will get right. That gets students used to the method, gives them some initial encouragement and emphasises that its not all about making them feel stupid.
A strategy that often works well is to prepare a sequence of questions on the same topic, but of increasing difficulty. Then you can pace things. If all (or nearly all) the students are getting the first few questions right, you can skip over a few questions and go straight into the more challenging ones. If they're finding the early ones difficult, you can slow down and give them more practice by using more of the easier questions.
There is no reason at all why you should not also interrupt the lecture at various points to ask free-response questions in the normal way. In fact, students may be more likely to answer in the interactive atmosphere of a PI lecture.
It may help to read through the question aloud first, before giving students a minute to think about the answer and then vote. (This is also useful for students listening to lecture recordings, if used).
Probably the most important thing is to give students enough time to think about their answers before getting them to vote. This is the most common criticism our students have made on their evaluations of Peer Instruction at Monash - just that they were sometimes not given enough time to think about their answer. How much time you allow depends on the question, though 1-2 minutes should be enough. Some straightforward questions might only require about 30 seconds thinking time. But if you say 'I'll give you a minute to think about it...', try to actually give students a whole minute. This can actually be quite difficult at first - to wait in silence for a whole minute while students think about their answers. Use a watch to make sure you give students enough time.
If you are using flash-cards, try to ensure that students all vote on their answers at the same time. For example, you might say 'OK, now on the count of three everyone hold up their cards at the same time please: 1, 2, 3 ...'. Doing this helps prevent students from looking around to see how other people are voting before making their own choice.
It is also very important is to give students enough time to talk to each other and argue about their answers. Here 2-3 minutes is usually about right (but it depends on how involved the question is). There's usually a sharp rise in noise levels as students start talking, which gradually dies down. When it first goes quiet, that's a good time to say 'Ok, let's vote on the answer again'. If possible, err on the side of giving students a little longer to talk to each other if they seem to need it, rather than cutting them off after exactly 3 minutes.
Don't worry if you find that most of the students are getting the right answer for many of your questions, so that there isn't enough disagreement to generate peer discussion. There is still a great deal of value in getting students to stop and think about the topic and then answer a question on it. Student evaluations have confirmed this -- students are very positive about the method even when peer discussions are more infrequent. A much more serious worry is if most students are getting the answers wrong most of the time. That suggests either that students are just not following the material at all, or that the questions are pitched a too high a level. It is counterproductive to have questions that students are getting wrong all the time - in that case, you should work on making the questions easier.
Be aware of the impact of using this method on the amount of material you'll be able to cover in a lecture. The question and discussion sessions do take up a fair chunk of time, so you probably won't be able to cover as much material in lectures as you're used to. You may need to think about cutting material from lectures and moving it to tutorials or seminars. The payoff is that the material you do cover in the lectures will be better understood, because students are having to actively engage with it during the lecture itself.