IntroductoryMacroeconomics · Chapter 1About 9 min

The evening paper says AI made the island grow seven percent,and you learn to ask: seven percent of what?

Seven percent

The evening paper on Halcyon costs two crowns. Tonight the front page has one word: GROWTH. Below it: AI boom lifts island economy seven percent.

You read it on the stairs. Tomas, the baker downstairs, reads over your shoulder.

1. T
   TomasSeven percent? My flour costs five percent more than last year.
2. You
   YouAnd your bread?
3. T
   TomasFive percent more too. I pay for an AI tool that plans the baking. Is that in there?
4. You
   YouAnd the free AI everyone uses for homework?
5. T
   TomasExactly. Did anyone count any of this?

Predict first

GDP grew by 7%. How much more did the island actually produce?

Counting what is made

The number is GDP: the market value of all final goods and services made on the island in a year.

Final means: what someone finally uses. Here that is Tomas’s bread. The wheat, the flour and the AI tool are all inside it. Step through the chain.

1. The farmer sells wheat for 20. Value added: 20.
2. The miller turns it into flour, sold for 50. Adds 30.
3. An AI firm sells the baker a planning tool for 10. Adds 10.
4. The baker sells bread for 100, after paying 60 for inputs. Adds 40.
5. Total value added: 100 — the price of the bread. All sales: 180. GDP is 100.

Adding all sales counts the wheat three times. Adding value added counts everything once.

You can also add up spending (C + I + G + X - M) or incomes (wages, profits, rents). All three give the same total.

What GDP does not see

The free AI assistant has no price. So it adds nothing to GDP, however useful it is.

The same goes for bread baked at home, unpaid care and free time. GDP counts what is sold, at market prices.

Prices and quantities

There are two kinds of GDP:

• Nominal GDP uses this year’s prices.
• Real GDP uses the prices of a fixed base year. It only moves when quantities move.

Their ratio is the GDP deflator, a price index for everything the island makes:

\text{GDP deflator} = \frac{\text{nominal GDP}}{\text{real GDP}} \times 100

With real growth g and inflation \pi:

1 + \text{nominal growth} = (1 + g)(1 + \pi), \quad \text{so nominal growth} \approx g + \pi

Model bench — nominal and real GDP

Challenge. Get the paper’s 7% nominal growth with no extra output at all.

All three lines start at 100: nominal GDP, real GDP at year-0 prices, and the GDP deflator.

2% real growth plus 5% inflation: nominal GDP grows 7.1% a year. After ten years nominal GDP has almost doubled. The island makes only about 22% more.

An AI’s answer

Spot the error

Question to an AI assistant How does AI show up in a country’s GDP?

Answer (written for this exercise)

¹ GDP measures the market value of the final goods and services produced in a period. ² A bakery’s paid AI subscription is an input, so its value is already inside the price of the bread. ³ Free AI assistants add their full usefulness to GDP, because people clearly value them. ⁴ If nominal GDP grows 7% while prices rise 5%, real GDP grows about 2%.

Which sentence is wrong?

Sentence 1 Sentence 2 Sentence 3 Sentence 4

You write to the editor: The island made about 2% more. The rest of your 7% is prices. And the free AI everyone uses isn’t in the number at all. Tomas pins it up by the till.

1. T
   TomasSo my AI tool counts, but your homework AI doesn’t?
2. You
   YouYours is inside the price of your bread. Mine has no price.
3. T
   TomasAnd the 7%?
4. You
   YouMostly your bread getting dearer.

Your prediction

You did not make a prediction at the start of the chapter. Here is what it asked:

GDP grew by 7%. How much more did the island actually produce?

The island made about 2% more. Prices rose about 5%. Together: the paper’s 7%.

Check yourself

Wheat sells for 20, flour for 50, an AI tool for 10, bread for 100. How much do these add to GDP?

180 crowns 100 crowns 110 crowns

Which of these is part of this year’s GDP?

A wedding speech written with a free AI assistant Flour bought by the baker A new loaf of bread bought by a household

Nominal GDP grew 7.1% and the GDP deflator 5%. How much did real GDP grow, in %? (One decimal.)

Your answer

Take it with you

This chapter on two pages

The ideas, the formulas, a worked example, four traps — and six questions to try on your own, with answers.

Download the sheet (PDF) 2 pages · 180 KB

Take it to your AI

Want to go further? Paste this into the AI you use. It asks the AI to quiz you, not to hand you answers.

I am learning how GDP is measured. A newspaper says: "AI boom lifts the economy seven percent." Prices rose about five percent over the same year, and many people use a free AI assistant.
Please act as my tutor. Do not give me the answers. Ask me one question at a time to help me work out:
1. how much of the seven percent is more output and how much is higher prices,
2. whether a business's paid AI subscription is counted in GDP, and how, and
3. whether a free AI assistant is counted in GDP, and why.
Wait for my answer after each question. At the end, tell me what I got right and correct anything I got wrong.

Key points

• GDP is the market value of all final goods and services made in a year.
• Add up value added, not sales. A firm’s AI tool is an input — already inside the price of what it sells.
• A free AI assistant adds nothing directly to GDP. Its price is zero.
• Nominal GDP uses this year’s prices. Real GDP uses fixed prices.
• Nominal growth ≈ real growth + inflation.

Next morning, Tomas puts the price of bread up again. Page two says fewer islanders are looking for work. To be continued — Chapter 2: inflation and unemployment.