Classroom · Economics
One lot, one sealed bid each, and the best loser sets the price.
Every student writes one private bid for a single lot. The highest bid at or above the reserve wins and pays the higher of the reserve and the runner-up's bid, never its own. The room sees what the lot sold for; each bidder sees privately what their bid did.
- Up to 600 people
- About 10 min
A practice run with fictional students. No real classroom or join code is created.
Try an answer on the phone. Lead the lesson from the screen.
On their phone
You are presenting
Setting up the room…
Lesson deck
Teach it as a ready-made lesson
Hook, how it works, the live game and takeaways. Edit anything.
How high would you go?
A ready-to-teach lesson deck: a hook, how it works, the live game and takeaways for the debrief.
6 slides · 1 activity
What it teaches
In a second-price auction your bid decides whether you win and never what you pay, so bidding exactly what the lot is worth to you is the one bid you cannot regret. Bid less and you risk losing a lot you would gladly have paid the price for; bid more and you risk winning at a price above its worth to you.
- Second-price auctions
Debrief, while the boards are still up
- 01
If you had bid more, what would have changed for you? And if you had bid less?
- 02
Did the winner's own bid change what they paid?
- 03
When would bidding above what the lot is worth to you backfire?
- 04
If the winner paid their own bid, would your number go up, down or stay put?
How it works
- 01
Add it to your library
Sign up free and pull the activity from Decka's built-in classroom catalog — one click copies it into your own library, ready to run from Decka or inside PowerPoint.
- 02
Students join by QR
Everyone scans from the projector and plays in their phone's browser. No app, no account, nothing to install.
- 03
You run the room
You move the activity phase by phase: collection closes, the boards resolve on the big screen, and the debrief happens while the results are still up.
What is a second-price auction?
It is a sealed-bid auction in which the highest bid wins but pays the second-highest bid, or the reserve if that is higher. It is also called a Vickrey auction, after the economist William Vickrey, who analysed it in 1961, and under it bidding your true value is a weakly dominant strategy: no other bid ever does better, and some do worse.
Played live, every student writes one whole number of credits for the same lot. The projector shows the reserve while bidding is open and the price once it closes, and each student privately sees what their bid did. Because the price is the runner-up's bid whenever the sale clears above the reserve, that one bid becomes public: tell the room so before the reveal.
FAQ
Second-price auction questions, answered
What is a second-price (Vickrey) auction?
A sealed-bid auction where the highest bid at or above the reserve wins and pays the higher of the reserve and the second-highest bid. Your bid decides whether you win, never what you pay.
Do students get a value card?
No. Each student decides what the lot is worth to them, so the debrief is about reasoning, not a check against a card.
Is every bid kept secret?
No bid appears beside a name. But the price the room sees is the runner-up's bid whenever the sale clears above the reserve, so that bid becomes public and the winner learns it exactly.
What is the reserve?
The lowest price the lot can sell at, shown on the projector while students bid: twenty credits by default. Bids are whole credits from zero to two hundred, and both are settings.
Does the class also play a first-price auction?
No. It is one sealed round, and the first-price contrast is the closing debrief question. The pricing rule is a lesson setting, so you can run a first-price lot separately.
How long does it take?
One sealed round; the saved default shows under the headline as "About N min", and every timer is a setting you control before you run it.
Do students need an app or an account?
No. Students scan a QR code from the projector (or open a link) and play in their phone's browser. Nothing to install and nothing to sign up for.
Does it work in PowerPoint or Google Slides?
In PowerPoint, yes: open the Decka add-in on a slide and choose the Classroom tile. Google Slides is not supported yet; there you present from Decka itself. Students play from their phones either way.
How many students can play at once?
Up to 50 participants per live activity on the free plan, 150 on Pro, and 300 on Badass.
More economics games to run live
- Closing time at the market
- You are the market
- Who really pays a tax?
- Two factories, one market, and the price you both set
- Two sellers, identical crates, and whoever is cheapest takes the lot
- One of you builds the factory first
- Send it and see what comes back
- Ten coins and nobody can stop you
- Spend the neighbourhood fund
- Four boats and a bay that belongs to nobody
- What is a flat worth to you?
- Three cars on one forecourt
- Tenants and landlords
- All economics activities
Ready to make your
presentations interactive?
Start free. No credit card required.