It’s a bold post title, I know. But this basic teaching idea is by far my favourite and for so many reasons.

The Traffic Lights

In an earlier post I shared a key terms traffic lights lesson idea that is based on the three colours representing different levels of knowledge. That idea evolved from this original one of having students use coloured cards to show their knowledge of content.

The idea couldn’t be more simple: you give students a set of traffic lights (pictured below) and then you ask a question. They hold up the colour that corresponds with their confidence:

  • Green – know it, got it, could teach it, we don’t need to go over it again, etc.
  • Yellow – I think I got it, not sure, have a couple of questions, need to go over it again, etc.
  • Red – No idea, have never heard of that word before, completely lost, etc.
Traffic Lights
Making these traffic lights takes about $5 in coloured card and 30 minutes with a laminator, but it’s well worth it

You’ll get instant feedback and visual data on student knowledge without having to do any marking!

Peer Teaching Idea

After students have shown me their cards for a particular piece of content, if we have a real range across the classroom I like to ask students to go and find someone who is holding up a green card. The “green students” then become teachers and explain the content to the yellows and reds.

I like this simple variation because it keeps kids honest – if they know they might have to explain it to peers, they’re less likely to try to bluff and hold up a green when they’re really not sure. It also means that all students can be working on the content at an appropriate level – I can differentiate in a matter of seconds with no planning while still having high levels of student engagement.


This is obviously a really effective formative assessment activity and can be great for doing a pre and post assessment in class. I like this because you get instant feedback on the progress (or lack thereof) you’ve made and the effect you’ve had as a teacher.

For example, just yesterday I measured my new IB Psych’ class’s confidence with the terms “independent variable” and “dependent variable.” By Grade 11 and after five years of science classes, one would hope this would be a lay-up for these kids. But like every year, I had a sea of uncertainty.

Traffic Lights - IVs and DVs
Every year my students start psychology without a solid grounding in IVs and DVs, or other experimental design concepts. The traffic lights are a great way to check this and measure progress.

So now I’ve got a sea of yellow I know I need to explain these terms. My experience told me to plan for this, so I already had this basic activity on IVs and DVs planned. It worked well as they could all identify (nearly all of) the IVs and DVs and by the end of the lesson they could all explain the difference between an IV and a DV (I know because they wrote this in their workbooks and showed me 🙂 ). Today in class I’ll begin with the traffic lights and see if our yellow sea has turned green.

Teaching Demand Characteristics: This pre/post idea can also be a great one to use to teach the concept of “demand characteristics.” Students can intuitively realize that they may have changed their colour because they were expected to learn that content and so by having to make their learning visual they may have changed their colour even if they weren’t completely confident. I think this is a good example of demand characteristics in action (which is also why I like to do my post-test on a different day).

Like most of the teaching ideas I love, this one is:

  • Quick
  • Takes zero planning time
  • Engages students
  • Provides immediate data on student learning
  • Can be adapted to any content or teaching

Many of you use this already, I’m sure, but I want to share it for those who haven’t seen it before. I know it took me a few years into my teaching before I was made aware of this idea and I really wish someone had have told me about it much, much earlier!

Sometimes I feel like a poster child for Paul Ginnis, but my credit for this idea once again goes to him as I picked it up from his workshop at our school a few years back. What I love is practical Pro-D and so I hope my blog posts are giving some practical Pro-D tips. (Here’s his book, and I promise I don’t get a % of the sales 🙂 ).

Do you use this already? Is there a better or different way of doing it? Feel free to leave a comment.