Welcome to the World of Aggregate Supply!
In the last chapter, we looked at Aggregate Demand—what everyone in the economy wants to buy. Now, we are looking at the other side of the coin: Aggregate Supply (AS). This is the total amount of goods and services that all the firms in an economy are willing and able to produce at different price levels.
Think of it like this: if Aggregate Demand is the "shopping list" of the nation, Aggregate Supply is the "output of the factory." Understanding this helps us figure out why prices rise (inflation) and why economies grow or shrink. Don't worry if it feels like a lot to take in at once; we'll break it down into bite-sized pieces!
1. What is Aggregate Supply?
In Microeconomics, you studied the supply of one product (like chocolate bars). In Macroeconomics, Aggregate Supply is the sum of every single business in the country. It shows the relationship between the Price Level (the average price of everything) and Real GDP (the total value of everything produced).
Quick Review:
• Aggregate Supply (AS): Total production in an economy.
• Real GDP: The volume of output, adjusted for inflation.
• Price Level: The average price of goods and services in the economy.
2. Short-Run Aggregate Supply (SRAS)
In the "Short Run," we assume that the costs of production—like wages and the price of raw materials—are fixed or "sticky." They don't change immediately when the price of the final product changes.
The Relationship with Price Level
The SRAS curve slopes upwards from left to right. This shows a positive relationship between the price level and the quantity supplied.
Why? Because if the price level rises but costs (like wages) stay the same, firms can make more profit. Naturally, they respond by producing more!
Shifts in the SRAS Curve
A shift in the SRAS curve happens when the costs of production for businesses change. If it becomes more expensive to make things, the curve shifts left (decrease). If it becomes cheaper, it shifts right (increase).
The "W.E.T.O." Mnemonic for SRAS Shifts:
• Wages: If trade unions negotiate higher pay, costs rise, and SRAS shifts left.
• Exchange Rates: If the currency gets weaker, imported raw materials become more expensive, shifting SRAS left.
• Taxes (Indirect): If the government increases VAT or business rates, SRAS shifts left.
• Oil Prices (Raw Materials): If energy or oil prices spike, it costs more to run factories and transport goods, shifting SRAS left.
Real-World Example: If the price of electricity doubles, almost every business—from a hair salon to a car factory—sees its costs go up. This causes the SRAS curve to shift to the left.
Key Takeaway:
SRAS is all about costs. If it costs more to produce, SRAS shifts left. If it costs less, it shifts right.
3. Long-Run Aggregate Supply (LRAS)
In the "Long Run," we assume that all factors of production (land, labour, capital) can change and that the economy is operating at its maximum potential. There are two main ways economists look at this:
The Classical (Neo-Classical) View
Classical economists believe that in the long run, the economy will always return to full employment. Therefore, the LRAS curve is a vertical line.
This means that no matter what the price level is, the economy has a fixed limit on what it can produce based on its resources. Raising prices won't make the "factory" any bigger in the long run.
The Keynesian View
Keynesian economists argue that an economy can be stuck below full employment for a long time (like during a depression). Their LRAS curve is shaped like a "backward L":
1. Horizontal section: There is lots of "spare capacity" (unemployment). Firms can increase production without raising prices.
2. Curved section: As we get closer to full capacity, resources become scarce and prices start to rise.
3. Vertical section: The economy is at Full Employment. You cannot produce any more, no matter how much demand there is.
Did you know?
Keynesians believe the government needs to step in to help the economy move, while Classical economists believe the market will eventually fix itself!
4. Shifting the LRAS: Increasing Potential
Shifting the LRAS is like "upgrading the factory." It’s not about costs; it’s about the quantity or quality of resources. When LRAS shifts to the right, it means the economy's productive potential has grown.
Factors that shift LRAS:
• Productivity: If workers become more skilled (better education) or machines become faster (new technology), we can produce more with the same resources.
• Investment: If businesses buy more robots, build better factories, or improve infrastructure (like 5G or better railways), LRAS shifts right.
• Labour Supply: If the population grows or people retire later, there are more hands to work.
• Enterprise: If the government makes it easier to start a business, more goods and services will be produced.
Simple Analogy: Imagine you are baking cookies.
• SRAS is like the price of flour changing.
• LRAS is like buying a bigger, faster oven. Even if the price of flour stays the same, the bigger oven means you can now bake 100 cookies instead of 50.
Key Takeaway:
LRAS is about capacity. To shift it right, you need better workers, better technology, or more resources.
5. Common Mistakes to Avoid
Mistake 1: Confusing a movement with a shift.
If the Price Level changes, you move along the SRAS curve. If Costs change (like wages), the whole curve shifts. Remember: Price Level = Slide; Costs = Shift.
Mistake 2: Mixing up SRAS and LRAS.
Think of SRAS as "how much we can produce today with our current costs" and LRAS as "the absolute maximum we could ever produce if we used all our resources perfectly."
Quick Review Quiz
1. If the government increases the minimum wage, which way does SRAS shift? (Answer: Left, because costs have increased.)
2. If a new invention makes internet speeds 10x faster for all businesses, which curve shifts? (Answer: LRAS shifts right, because productivity and potential have increased.)
3. According to Classical economists, what shape is the LRAS curve? (Answer: Vertical.)
Don't worry if the two different LRAS curves seem confusing! Just remember that Classical economists are "optimists" who think the economy is usually at full strength, while Keynesians are "realists" who think the economy can sometimes get stuck in a rut.