David Franklin

So Trump was 29% likely to win. What does 29% mean?” he asks. This is an odd question for many: they’re doing a Master’s degree at Harvard, and they’re being asked what a percentage means. The question is aiming at the gut reaction of the brain to the number. Inevitably, students think it might be a trick question. Dan waits a while, and when no-one raises their hands, he breaks away from the example to tell a story: “You know, when I first started teaching, I was terrified of silence. I thought, ‘oh my god, I’ve got to do something, they’re not saying anything’.” The class laughs: he has eased the tension created by the silence. “The more I taught, the more I realised that silences are important in a class – they give time for people to think. These days, I’m not afraid of silence at all.” After a few seconds, a woman puts up her hand. “Well, obviously, I knew that it meant there was some chance that he would win. But it was still a shock that the 29% happened.

In Dan’s case, the interest in policymaking is so central to the students’ presence at Harvard that it would be foolish to run a statistics course that did not acknowledge it. He goes as far as to build this into the purpose of the course: as we heard earlier, his purpose is “not just to maximise learning about statistics, but also to maximise learning of the skills that will be useful to have out there in the world.

Maximising enjoyment All students want to enjoy their classes. This simple truth means that teachers who can make learning fun will, other things equal, be more successful. If the only way students can enjoy themselves is to ignore the class and play on their phones, then student enjoyment is a headwind that slows the boat’s progress. By making learning fun, teachers can adjust the sails to take advantage of the wind and speed the boat up. The progress it makes may not be directly towards our destination, but we can use the sails nonetheless to pick up speed and get closer to it than we would otherwise have done.

The brain has conflicting goals: to provide you with information, and to reduce your anxiety about the worrying outcome. If you wanted Clinton to win in 2016, your brain achieved both goals by accepting the 30% figure but telling you it would not happen.

The phrases ‘certainty is an illusion’ and ‘think probabilistically about the world’, both introduced in the first class, are the first two examples of high-level concepts which Dan calls airport ideas.

The great economist John Maynard Keynes is supposed to have said “when the facts change, I change my mind. What do you do, sir?

I remember he said something like ‘this should be completely obvious to you’, and to me that was crushing… we had a conversation after the mid-term exam, in which the class had averaged 20 out of 90. It was 25 years ago, and I still remember what he said: ‘Frustration is necessary for learning. This idea that you can enjoy learning is a very American idea’.” Dan pauses, the memory of that conversation etched on his face. “I felt so offended by that claim. My professor felt that to learn, you had to push yourself. One of my dreams was to go back to Venezuela[7] and start a university, and I vowed that I would write in the walls of the university that frustration was not necessary for learning.

Availability bias prevents us from setting our prior beliefs appropriately, whereas confirmation bias stops us from updating them for new information.

For these ‘future leaders’ in the classroom, it is more important to understand the psychology of certainty. Often, we believe what we want to believe. Dan starts with an example of the 2016 Presidential Election in the United States. He asks the question: “Relative to what you expected to happen, how surprised were you when you learned that Trump had won the election?

He asks the 80 students to respond based on their ‘gut feeling’. Again, students are given five options, ranging from ‘less than 1%’ to ‘above 40%’. About half of them believe the true answer is less than 5%, of which plenty go for the ‘less than 1%’ option. Only 1 in 6 get it right, picking the highest option: it turns out that the true figure is 41%. He invites those people – 13 in total – to stand up.

Dan’s goal, taken from his mentor Richard Zeckhauser, is to get students to think probabilistically about the world. This means engaging with the challenge of understanding and accepting what 29% means in the context of a Trump victory, and fighting the brain’s natural inclination to see things in binary terms.

There is also something powerful in the concept of an ‘airport idea’. On the surface, it links with Dan’s plea for what students should do if they meet him in an airport in five years’ time. But there are hidden suggestions too: the airport carries an association of being high-level, and fits in with the course’s aim of empowering the students with the tools they need to effect change. Once the course is over, they will disperse to airports across the world and put these ideas into practice in their home countries.

Dan’s use of two-stage exams kills two birds with one stone. Firstly, he maximises learning by ensuring that the exam itself is a learning experience. Second, in doing so, he makes clear that the grade is less important than the learning. Two-stage exams have not yet ‘taken off’ around the world, and grades remain the key outcome of most exams for most students. Dan, though, has taken advantage of his position in a graduate university environment to push the idea forward.

The first key idea is that when you have a challenge for which measuring progress is hard, the ability to adapt is just as important as the ability to plan.

With 80 people, the size of this classroom, the probability that there will be no shared birthdays is so tiny as to be virtually impossible.