Efficient teaching: 5-second wait time

I’m not a fan of asking questions in the middle of a lesson that are designed to elicit raised hands. But once in a while, it makes sense.

For example, at the start of class, I often ask if anybody has any particular questions or concerns, or some cool science they’d like to share. In the middle of a lesson, I might ask if anybody wants some additional clarification about some point.

Unless you’re taking a quick poll, then if you’re asking a question that involves raised hands, it’s a good idea to wait five seconds.  Five seconds is a long time. One watermelon, two watermelon, three watermelon, four watermelon, five watermelon. However, that kind of wait time is necessary if you’re looking for reflection and to get a response from the people who are most likely to benefit from responding.

“Who knows the answer to X?” “Did you understand Y?” “Did you catch the reference to Z?” All need some lag time before people would-be hand-raisers might get involved.

For example, a few weeks ago we were about to sort out the math of an ANOVA in my graduate biostatistics course. I mentioned that the ANOVA was invented by the biologist Ron Fisher, as a part of the advances in the Modern Synthesis.

Then it occurred to me, wait, even though this is a graduate class in biology, the students might not have heard of the term, “Modern Synthesis.” (Which I happened to just mention on this site last week, actually.)

So I asked, “Does anybody want me to tell the story of the Modern Synthesis?”

No hands.

For about three or four seconds.

Then, pretty much everybody in the room raised a hand. Not in a ‘you’re-going-to-tell-me-anyway-so-I’ll-raise-my-hand’ way. I don’t think so, at least.

Then I asked, who can tell me anything about what Ron Fisher did, other than the Fisher’s Exact Test? And I waited at least five seconds. And still, after that period of time, nobody raised their hands. Which told me, for sure, that nobody knew anything whatsoever about Ronald Fisher. (Which gave me a sad, but I lived with it just fine.)

The moral of this story is:

If you’re going to ask a question and have people raise their hands, it’s useful and important to count silently to yourself for five seconds before you do anything else. Just pretend that you’re a rusher in flag football and are counting up to five watermelon.