Using ModelsUsing ModelsChapter 2-3

What is a modelWhat is a model

Simplified representations of reality play a crucial role in economics.

Models in EconomicsModels in Economics

A model is a simplified representation of a real situation that is used to better understand real-life situations.

Create a real but simplified economy Simulate an economy on a computer

Ceteris ParibusCeteris Paribus

Economist make many assumptions as they create these models.

The “other things equal” assumption means that all other relevant factors remain unchanged.

Using ModelsUsing Models

Positive economics is the branch of economic analysis that describes the way the economy actually works.

Normative economics makes prescriptions about the way the economy should work.

A forecast is a simple prediction of the future.

Positive vs.. NormativePositive vs.. Normative

Facts and forecasts Usually debate is based on accuracy of data

The question of how it should be Usually debate is based on perspective of

fairness

Using ModelsUsing ModelsEconomists can determine correct answers for positive questions, but typically not for normative questions, which involve value judgments.

The exceptions are when policies designed to achieve a certain prescription can be clearly ranked in terms of efficiency.

It is important to understand that economists don’t use complex models to show “how clever they are,” but rather because they are “not clever enough” to analyze the real world as it is.

When and Why Economists When and Why Economists DisagreeDisagree

There are two main reasons economists disagree:

They may disagree about which simplifications to make in a model.

They may disagree about values.

Simplifying Assumptions Simplifying Assumptions making life complicatedmaking life complicated

Since economist rely heavily on modeling

Which are simplified representations of reality

Economist argue about which simplifications are appropriate.

Simplifying assumptionsSimplifying assumptions

Since they use different models with different assumptions they end up with different conclusions.

Values can differValues can differ

Different people (economist are people too) bring their values with them to any analysis Tax example in the book

FinallyFinally

Economics is a method NOT a set of conclusions!