Source: Comprehensive Overview of Microeconomic Theory Concepts (Texas A&M University)
Tags: microeconomics, scope of microeconomics, positive statements, normative statements, markets, industries, CPI, consumer price index, inflation, rate of inflation, market basket, cost of living, micro vs macro
Microeconomics studies how individual consumers and firms allocate scarce resources, in contrast to macroeconomics which looks at aggregate phenomena. A core skill is distinguishing positive (testable) from normative (value-laden) statements. The Consumer Price Index tracks price changes in a representative basket of goods and is the standard tool for measuring inflation.
Microeconomics
The branch of economics concerned with the behaviour of individual consumers and firms, and how they make decisions about allocating limited resources.
Macroeconomics
The branch of economics dealing with aggregate phenomena: unemployment, inflation, interest rates, and national output.
Positive statement
A factual, testable claim about the world as it is or will be. Grounded in empirical evidence or models.
Normative statement
A claim involving a value judgement about what ought to be. Subjective and not empirically testable.
Market
Any platform or arrangement where buyers and sellers interact to exchange goods or services. Can be physical, digital, local, or global.
Industry
The collection of firms producing similar or related products. Focuses on the production (seller) side, unlike a market which includes both buyers and sellers.
Consumer Price Index (CPI)
A measure that tracks changes in the price of a large, representative basket of goods and services over time. Used to gauge inflation and cost of living.
Inflation rate
The percentage change in the CPI over a given period. Indicates how much the general price level has risen (or fallen).
Market basket
The specific bundle of goods and services whose prices are tracked to construct the CPI.
Resource allocation
The process by which scarce resources are distributed among competing uses and users.
Microeconomics asks: how do consumers decide what to buy? How do firms set output levels? What happens to demand and supply when prices or incomes change?
It examines markets and industry interactions at a granular, individual level.
Macroeconomics, by contrast, concerns itself with economy-wide aggregates: total output, unemployment, inflation, and interest rates.
Positive statements describe what is or what will be. They can be tested against data.
Example: "An increase in the price of petrol leads to a decrease in the quantity demanded."
Normative statements express opinions about what should happen. They cannot be confirmed or refuted with data alone.
Example: "The government should reduce taxes to stimulate growth."
Economic analysis aims to stay grounded in positive assessment; policy decisions inevitably involve normative judgement as well.
A market includes all participants in buying and selling a good or service, in whatever form that exchange takes (local, online, stock exchange, etc.).
An industry is defined by the firms that produce similar products, e.g. the automobile industry is all car manufacturers.
Key difference: markets are about the interaction between buyers and sellers; industries zoom in on the production side only.
The CPI is constructed by recording prices for a representative market basket of consumer goods and services.
Changes in the CPI over time reflect how the overall price level is moving.
The inflation rate is calculated as the percentage change in the CPI between two periods.
Inflation rate formula:
Inflation rate = ((CPI_new – CPI_old) / CPI_old) × 100
Example: CPI rises from 200 to 210 over a year. Inflation rate = ((210 – 200) / 200) × 100 = 5%.
⚠️ The positive vs normative distinction is a perennial exam favourite. If a statement contains "should," "ought to," or any value judgement, it is normative.
⚠️ Market ≠ industry. A market includes buyers and sellers; an industry is sellers/producers only. Exam questions often test whether you can tell them apart.
⚠️ CPI percentage change is the inflation rate. Be comfortable computing it from two CPI values.
Q: What is the key difference between a positive statement and a normative statement?
A: A positive statement is factual and testable against evidence (describes what is). A normative statement involves a value judgement about what ought to be and cannot be empirically tested.
Q: If the CPI rises from 150 to 160 over a year, what is the inflation rate?
A: (160 – 150) / 150 × 100 = 6.67%.
Q: How does a market differ from an industry?
A: A market encompasses all buyers and sellers interacting to exchange a good or service. An industry refers only to the group of firms producing similar products (the supply side).
Q: Give an example of a positive statement and a normative statement about taxation.
A: Positive: "Raising the income tax rate reduces disposable income." Normative: "The government should raise income taxes to fund public services."
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