Teacher's guide · Experiment 001

Ad Auction Live

Every Google ad has just won an auction. This guide explains how the game models that auction, which results to expect, and what to click, say and watch for in each round.

About 10 minutesExactly 4 teams3 roundsOne screen + paper
Open the game →Jump to the cheat card
The idea

What students learn

1. Quality beats money

Ad Rank is bid × quality, so a strong ad with a small bid can beat a weak ad with a big one.

2. You pay just enough to win

Each ad pays only enough to beat the ad below it: a simplified generalised second-price auction.

3. The top spot is not always the best deal

Profit depends on what a click is worth to you, not on position alone.

4. AI Overviews change the maths

Round 3 halves every position's clicks, in line with Pew Research Center (2025): 8% of visits with an AI summary led to a click on a result, against 15% without.

Good for digital marketing, search marketing, e-commerce and microeconomics classes. You need a laptop on the classroom screen and paper for bids; students do not need devices.

Read first

Five golden rules

  1. Do not reload, close the tab, or click a link on the game page once you start.The game keeps everything in the open page only. A reload, or clicking a footer link, clears all profits.
  2. There is no back button.Once you bang the gavel, that round's profit is banked. Read the four bids back before you press it.
  3. Timers never start themselves and never move the game on.Press Start timer. At 0:00 three bells chime and the clock turns pink.
  4. "Restart game" needs two taps within 3 seconds.One accidental tap does nothing.
  5. Once loaded, the page runs without Wi-Fi.Open it before the lesson, and do not reload.
How it is built

The auction rules

The four shops

TeamShopQualityWorth per clickBid shown at the start
AMegaSport UK, big national chain3/10£6£4.00
BDundee Kicks, indie shop in town9/10£4£2.00
CRunFast Online, online-only store5/10£5£3.00
DBargainBoots, discount website6/10£3£1.50

"Worth per click" is what one click earns the shop on average. For example, if 1 in 20 visitors buys and each sale makes £80, a click is worth £4. The bids shown at the start are an example: any bid you do not overwrite is used as it is. Before Round 1 only, the small − and + buttons let you change a shop's quality or worth.

Ad Rank = bid × quality
Minimum Ad Rank to appear = 2
Price per click = (Ad Rank of the ad below ÷ your quality) + 1p, never more than your bid
The lowest ad shown pays a floor price of £0.10
Clicks: position 1 = 100, 2 = 60, 3 = 35, 4 = 15 (Round 3: 50, 30, 18, 8)
Profit = clicks × (worth per click − price per click)
  • Bids are capped at £10. Ties in Ad Rank go to the higher quality.
  • Profit can be negative if a team pays more per click than a click is worth.
  • Rounds 2 and 3: each team may pay £40 once to fix its landing page: quality +2, up to 10. The £40 comes off its profit at once. Tapping the button again before the gavel undoes it.
  • The winner is the team with the most profit after three rounds, not the most top ads.
Worked answers

Results you can predict

All of these come from the game itself, with the other shops on their starting bids.

PositionShopAd RankPays per clickClicksProfit
#1Dundee Kicks (£2.00 × 9)18£1.68100£232.00
#2RunFast Online (£3.00 × 5)15£2.4160£155.40
#3MegaSport UK (£4.00 × 3)12£3.0135£104.65
#4BargainBoots (£1.50 × 6)9£0.1015£43.50

The biggest bidder comes third and pays the highest price per click. You can use this table as a paper version if the technology fails.

MegaSport: raise the bid or fix quality?

Bid £5.50: Ad Rank 16.5, position #2, pays £5.01 a click.

Keep £4, fix the page (quality 5): Ad Rank 20, position #1, pays £3.61 a click, profit £239 (£199 after the £40 fix).

"We won and lost money"

If MegaSport bids £10 in Round 1, it takes #1 but pays £6.01 a click (18 ÷ 3 + 1p) for a click worth £6: profit −£1.00. Pause the class on this one.

Round 3, same bids

Positions and prices stay the same, but clicks halve, so profits roughly halve (Dundee Kicks £116 instead of £232). Is the top spot still worth paying for?

Dundee Kicks and the fix

At quality 9, the £40 fix only adds 1 point (the maximum is 10). A good prompt: who gains most from improving quality?

10 minutes

Before the lesson

  • Open lab.yingwu.co.uk/ad-auction/ in Chrome or Edge on the classroom computer.
  • Press Full screen. Esc leaves full screen.
  • From the back of the room, zoom with Ctrl + + (Mac: Cmd + +) if needed. Zooming does not reset the game.
  • Test the sound: the button at the top right shows the current setting (🔊 Sound is on). Click it twice: off, then on again, which plays a test knock. Check the computer's volume and that sound goes to the room speakers.
  • Do a quick dry run, then reload (fine before the real game starts).
  • Prepare a slide or board showing the four shops, their quality and worth per click.
  • Give each team paper for its sealed bids.
In class

Step by step

About 10 minutes in total.

  1. 0

    Explain the rules and form teams

    2 min
    Say
    "Every time you search, the ads you see have just won an auction in a split second. And the biggest wallet doesn't always win. Ad Rank is your bid times your quality. Never pay more than a click is worth to you. The winner has the most profit after three rounds."
    Students
    Split into four teams, one shop each (rows work well). Each team picks a runner.
    Note
    Tell students it is a classroom model: Google's real Ad Rank also weighs ad assets, context and thresholds, and Quality Score is a diagnostic, not a live auction input.
  2. 1

    Round 1: sealed bids

    2 min · timer 1:30
    Round 1 screen with the brief, a 1:30 clock, the open rules panel and four shop cards.
    Round 1 opens with the rules panel expanded.
    Click
    1. Press Full screen, then Start timer.
    2. When time is up, all four runners hold up their bids at the same time.
    3. Click each Sealed bid per click box, select all (Ctrl+A) and type the bid. Enter jumps to the next shop.
    4. Read the four bids back, then press Bang the gavel.
    Watch for
    • Type numbers only, with a full stop: 2.50. No £ sign and no comma: "£2" is read as £0 and "2,50" as £2.
    • An empty box or 0 means the ad is not shown.
    • Leave the small − and + buttons alone unless you deliberately want to change a shop.
    Four shop cards with quality, worth per click, a large sealed bid box and profit so far.
    The bid boxes start with example bids. Overwrite all four.
  3. 2

    The reveal

    1 min
    Screen
    Ad Rank bars with the sum under each (left); what the searcher sees, with each ad's price, clicks and profit (right); a scoreboard with the price and profit maths; and a yellow lesson banner. Any ad under Ad Rank 2 is listed in red as not shown.
    Say
    Read the banner. Then: "Who bid the most? Where did they land? What did they pay per click compared with the winner?"
    Round 1 reveal: Ad Rank bars, sponsored search results and the scoreboard with the lesson banner.
    Round 1 with the example bids: Dundee Kicks wins with £2.
    Round 1 scoreboard table showing position, bid, price per click, the price calculation, clicks, profit and profit maths.
    The scoreboard shows every calculation, so students can check the maths.
  4. 3

    Round 2: fix your landing page?

    2 min · timer 1:00
    Click
    1. Press Next round (the pink button under the shop cards), then Start timer.
    2. For each team that pays for the fix, press its Fix landing page: quality +2 for £40 button. It turns green.
    3. Type all four new bids, read them back, press Bang the gavel.
    Say
    "You can pay £40 to improve your landing page: quality plus 2. Is it worth it? How many rounds until it pays back?"
    Watch for
    Bids carry over from the last round: overwrite all four. Each team can buy the fix only once.
    Round 2 shop cards: MegaSport's fix button is green, its quality shows 5/10 and £40 has come off its profit.
    MegaSport bought the fix: quality 3 to 5, profit down £40.
  5. 4

    Round 3: an AI Overview appears

    2 min · timer 1:00
    Click
    1. Press Next round, then Start timer.
    2. Teams that have not fixed their page can still do it now.
    3. Type four bids, read them back, press Bang the gavel.
    Say
    "Google now shows an AI summary above the ads, and every position gets about half the clicks. Is the top spot still worth the price? Does anyone want to bid lower?"
    Round 3 reveal: the search results show an AI Overview box above the ads and halved click numbers.
    The AI Overview pushes ads down and halves the clicks.
  6. 5

    Final results and debrief

    1 to 2 min
    Click
    Press Final results: a podium ranked by profit, a banner comparing "top ad most often" with "most profit", and four debrief questions.
    Say
    Pick one: "Why did a small indie shop beat a national chain with a lower bid?" or "When the AI Overview halved the clicks, should a client still pay for the top spot?"
    Final results podium ranked by profit with the debrief questions.
    The winner is the team with the most profit.
Fixes

If something goes wrong

ProblemWhat to do
A wrong bid was gavelledThe profit is banked and cannot be undone. Say so and let that team adjust next round. Do not restart for one typo.
"Fix landing page" is greyThe team already bought it, or its quality is already 10.
An ad is "not shown"Its Ad Rank was under 2 (for example a bid of £0.20 at quality 9). A useful teaching point about minimum thresholds.
A profit is negativeThe team paid more per click than a click was worth. Ask them why.
The page reloadedEverything is cleared. Reopen and ask teams for their running totals from their paper notes, or continue as a fresh game.
No Wi-FiIf the page was already open, carry on. Otherwise use the worked answer table above on paper.
No soundThe top-right button should read "🔊 Sound is on". Turn it off and on again to hear a test knock, then check the computer's volume and output device.
Keep on your phone

Cheat card: the button order

  1. Full screen, then Start timer (1:30)
  2. Type four bids: numbers only, with a full stop
  3. Bang the gavel, read the banner
  4. Next round, Start timer (1:00)
  5. Tap "Fix landing page" for teams that pay
  6. Type four new bids, Bang the gavel
  7. Next round, Start timer (1:00), four bids, Bang the gavel
  8. Final results and one debrief question
Sources

Behind the model

  • Edelman, B., Ostrovsky, M. and Schwarz, M. (2007) 'Internet advertising and the generalized second-price auction: selling billions of dollars worth of keywords', American Economic Review, 97(1), pp. 242-259.
  • Google Ads Help (n.d.) About Ad Rank. support.google.com
  • Google Ads Help (n.d.) About Quality Score. support.google.com
  • Pew Research Center (2025) Google users are less likely to click on links when an AI summary appears in the results, 22 July. pewresearch.org
  • Varian, H.R. (2007) 'Position auctions', International Journal of Industrial Organization, 25(6), pp. 1163-1178.

A simplified classroom model. Click numbers per position are illustrative. The shops are fictional.