Develop models to explain how the economy works, for example theories of supply and demand or the circular flow of income
Theory
Can be expressed in words
Model
Expressed in mathematical terms, requires greater precision
The purpose of theories and modelling is to explain why something is as it is
Theories and models are simplified to make them more useful
Assumptions
Must be made when developing economic models and theories due to the many variables that can change
Ceteris paribus
All other things remaining equal
Economics is a social science, unlike natural sciences it is difficult to set up experiments to test hypotheses
Economists tend to come up with very different conclusions for a particular set of data
Economics is not a science because it studies human behaviour which cannot be reduced to scientific law
Groups of individuals are much more predictable than individuals themselves, and much of economics deals with groups rather than individuals
Positive statement
Objective statement made without value judgements or emotions, can be tested to be proven or disproven
Positive statements
Raising taxes will lead to an increase in tax revenue
Warm weather will lead to an increase in ice cream sales
Normative statement
Subjective statement based on opinion, cannot be proven or disproven, often includes words like 'ought', 'should', etc.
Normative statements
The free market is the best way to allocate resources
The government should increase taxes
Economists tend to use positive statements to back up normative statements
Value judgements can influence economic decision making and policy
Scarcity
The basic problem of economics, people have finite needs but infinite wants, and resources are finite and limited
Renewable resource
Resource of economic value that can be replenished or replaced on a level equal to consumption
Renewable resources
Oxygen
Solar power
Fish
Non-renewable resource
Resource of economic value that cannot be readily replaced by natural means on a level equal to consumption
Non-renewable resources
Fossil fuels (coal, oil, gas)
Opportunity cost
The cost of one thing in terms of the next best option which has been given up
Opportunity cost
If you buy a chocolate bar instead of a bag of crisps, the opportunity cost is the bag of crisps you could not buy
Production possibility frontier (PPF)
Shows the maximum possible combinations of capital and consumer goods that the economy can produce with its current resources and technology
The PPF is typically drawn as a curve because the first resources switched from capital to consumer good production are resources that are not adding much to capital goods but will be much more productive in the production of consumer goods, and vice versa
The PPF gives no indication of which combination of goods is best, economics is concerned with explaining why a country chose a particular production point
Points on the PPF
Represent the maximum productive potential of the economy, the most that the country can produce
Moving from point A to point B on the PPF
The opportunity cost is 30 capital goods for an extra 15 consumer goods
Producing 60 capital goods
The opportunity cost is 20 consumer goods
Producing 1 consumer good
The opportunity cost is 3 capital goods
Producing 1 capital good
The opportunity cost is 1/3 of a consumer good
Purple arrows on the PPF
Indicate economic growth, the economy can produce more of both goods
Orange arrows on the PPF
Indicate economic decline, the economy can produce less goods than previously
Economic efficiency
Achieved when resources are used for their best use, all points on the PPF are efficient
Point A on the PPF
Possible and efficient production
Point B on the PPF
Possible but inefficient production, not maximising output
Point C on the PPF
Unobtainable production, beyond the economy's current resources and technology
Factors that could cause a fall in production
Natural disasters
Natural resources running out
Decrease in the quantity/quality of labour, due to war, migration or a fall in spending on education
Economic efficiency
Achieved when resources are used for their best use. At all points on the PPF, resources are allocated efficiently.