Reference: Acemoglu, Laibson, and List (2014) Economics, chapters 1-2.
Economists investigate:
Buy iPhone X or not
Economists investigate:
Apple: how many iPhone X to produce
Economists investigate:
Get married or not
Economists investigate:
Study now or later
Economists investigate:
Vote for LDP or not
Economists think:
Economists think:
It meets each individual's objective
Economists think:
Within the budget
Within 24 hours a day
Among the list of candidates
Example:
(Is it the best?)
Intellectual fun
Learning English
Love politics
etc.
(Is it affordable?)
Another fun course
Difficult to get credit
etc.
Economists also investigate:
Price of low-cost airline tickets
Economists also investigate:
Traffic jam
Notice:
Notice:
Many people choose to drive
Notice:
Many people choose to drive
More traffic jam
Notice:
Many people choose to drive
More traffic jam
Some start using public transport
Notice:
Many people choose to drive
More traffic jam
Some start using public transport
Less traffic jam
Notice:
Many people choose to drive
More traffic jam
Some start using public transport
Less traffic jam
Economists think:
Example:
Proof
of a great course
More students
join the course
Example:
Proof
of a great course
More students
join the course
Less interaction with me
during lectures
Some students
drop out
Example:
Proof
of a great course
More students
join the course
Less interaction with me
during lectures
Some students
drop out
Proof
of a bad course
More students
drop out
Example:
Proof
of a great course
More students
join the course
Less interaction with me
during lectures
Some students
drop out
Proof
of a bad course
More students
drop out
More interaction with me
during lectures
No more students
drop out
Example:
Proof
of a great course
More students
join the course
Less interaction with me
during lectures
Some students
drop out
Proof
of a bad course
More students
drop out
More interaction with me
during lectures
No more students
drop out
The adjustment process continues
Example:
Proof
of a great course
More students
join the course
Less interaction with me
during lectures
Some students
drop out
Proof
of a bad course
More students
drop out
More interaction with me
during lectures
No more students
drop out
The adjustment process continues
Economists think:
building
Our knowledge comes from
and checking if the models are
Economists think:
building
Our knowledge comes from
and checking if the models are
Simplified
representation
of the world
Economists think:
building
Our knowledge comes from
and checking if the models are
Simplified
representation
of the world
Economists think:
building
Our knowledge comes from
and checking if the models are
Many models
logically possible
Economists think:
building
Our knowledge comes from
and checking if the models are
Many models
logically possible
Allow us to pick the best model
Economists think:
building
Our knowledge comes from
and checking if the models are
To check a model's consistency with data, economists:
and
Example:
You: No, because China is still not a democracy.
Economist: But that could just be an outlier.
Figure 1 from Acemoglu et al. (2008)
Economist: No, that's a correlation, not a causality.
You: The higher GDP per capita, the more democratic
to tease out causality from correlations
cf. drug tests
e.g. weather
e.g. close elections
to tease out causality from correlations
cf. drug tests
e.g. weather
e.g. close elections
II
+
+
Summary