This is Lecture 1: Political Science and the
Scientific Method
By the end of this lecture, you should:
Be familiar with the scope and focus of political
science
Be familiar with the basic steps of the scientific
method
Understand how to apply the scientific method
to political science research
Understand the purpose of scientific research
What is political science?
Political science is the study of politics
in a scientific manner.
Political outcomes deal with any activity
that is associated with public decision-making.
Public decisions are decisions that affect
large groups of people and are enforced by
authoritative means.
Political scientists strive to both describe
and explain any activity that is associated
with these political outcomes.
There are many different types of political
outcomes, and therefore, there are many different
subfields in political science that focus
on different types of outcomes.
For example, political scientists who study
politics within different countries throughout
the world study comparative politics.
For example, some comparativists study topics
such as voter turnout across countries.
They try to explain why citizens in some countries
are more likely to vote than citizens of other
countries are.
Comparativists also study topics such as candidate
selection across countries.
They try to explain why party leaders in some
countries have more control over candidate
selection than party leaders in other countries.
Another field of study is democratization.
Political scientists who study democratization
try to explain why some non-democratic regimes
are more likely to become democracies and
why some are not.
Next, international relations is the study
of politics between countries.
International relations scholars try to explain
outcomes such as why some countries go to
war, while other countries are more likely
to trade with each other.
They also try to explain the role that international
organizations play in the international system.
For example, some scholars are interested
in how the United Nations and NGOs influence
human rights practices in countries throughout
the world.
And last, American Politics is another subfield
in political science.
Americanists specifically focus on describing
and explaining political outcomes in the United
States.
American Politics includes such topics as
Congressional voting behavior, Presidential
decision making, voting behavior among American
citizens in different socioeconomic groups,
variations in politics across US state legislatures,
and policymaking and policy implementation.
Now we are going to talk about the scientific
process.
What is science?
Science is not a collection of facts, or a
static set of beliefs.
Science is a tool we use to try to explain
how the world works.
Within the scientific process, it is important
to test all potential explanations of political
outcomes, even if you do not think they are
plausible.
Knowing which explanation are supported by
the evidence is just as important as knowing
which explanations are not supported by the
evidence.
This allows to gather evidence that helps
us have more confidence in some explanations
of political outcomes than other explanations.
It is also important to be open to criticism.
Criticism allows us to recognize what we know
and what we do not know.
If we do not know what we do not know, then
we will never be able to correct our misunderstandings
of political outcomes.
In addition, finding out what we do not know
leads us to new research ideas, further advancing
the scientific process.
It is also important to note that within science,
all knowledge is tentative.
We may have an idea of how the world works
today, but we might find out we are wrong
with new research findings.
Now we will talk about the steps of the scientific
process.
The scientific process starts out with a question.
We want to know why we see variations in certain
outcomes.
Those outcomes are called dependent variables.
For example, many political scientists want
to know why some people in the US vote for
Democrats, while other people vote for Republicans.
The dependent variable in this case is “Vote
choice.”
Note that it is called a variable because
the outcome we are interested in varies.
It includes both people who vote for Democrats
and Republicans.
If you ONLY examined individuals who voted
for Democrats, and ignored those who voted
for Republicans, then you would not have a
“variable.”
Also note that the aforementioned question
was general: why do some people vote for Democrats,
while other people vote for Republicans?
In science, we focus on general questions,
not specific ones.
We do not examine a single individual’s
vote choice, we focus on many individuals’
vote choices.
The next step in the scientific process is
developing a model to explain why you see
variation in the dependent variable.
A model is a simplification of the world.
In our models, we choose one factor that influences
variation in our dependent variable.
We ignore all the other factors that could
influence our dependent variable.
The factor we focus on is called an independent
variable.
For example, many political scientists argue
that income affects vote choice.
Individuals who low income need more government
services, so they are more likely to vote
for Democrats, because Democrats are more
likely to support and expand government programs.
On the other hand, individuals who are high
income do not like high taxes.
As such, they are more likely to vote for
Republicans because Republicans are more likely
to support tax cuts for the rich.
As you can see, when you create a model, you
are basically telling a story about how the
world works.
You are explaining how your independent variable-
in this case, income
influences your dependent variable, vote choice.
Note that in the model I presented, I made
assumptions about the preferences of high-income
individuals.
In every model, political scientists make
assumptions.
In this case, I assumed, for example, that
high-income individuals did not value redistributing
their income to the poor through government
services.
I made this assumption because intuitively
it made sense.
However, while I think this assumption applies
to many wealthy people, I do not think this
assumption does applies to all wealthy people.
So why do I make a blanket assumption here
that applies to all wealthy people?
Simply because it makes writing the theory
easier.
The next step in the scientific process is
deriving hypotheses from our model.
A hypothesis is a one sentence statement we
derive from our model.
It tells us how our independent variable should
influence our dependent variable.
And it is testable or observable in the real
world.
We should be able to collect real world data
and determine if the statement is valid or
invalid.
So, using the example from our previous slide
where we discussed the influence of income
on voting behavior, this here is a one sentence,
testable statement from that model that describes
how the independent variable should influence
the dependent variable could be:
“As a voter’s income increases, he is
more likely to vote for a Republican than
a Democrat.”
This statement is testable because we could
conduct a survey and ask voters about their
vote choice and their income.
Then we could see if high-income voters are
more likely to vote for Republicans than Democrats.
So, by deriving testable hypotheses from our
models, it allows us to gather evidence that
either supports or fails to support our model.
The next step is actually collecting and analyzing
the data to provide support or fail to support
our hypothesis.
In this class, we will be focusing on collecting
and analyzing large N datasets, with hundreds
and thousands of observations.
Since we have so many observations, we will
need to use statistics to analyze the data.
Some political scientists focus on small n
datasets, that only have a handful of observations.
We generally call their types of studies case
studies.
In their case studies, they use thick description
to analyze their data.
This approach is beyond the scope of this
course.
Note that in our large N datasets, we have
to collect data both on our dependent and
independent variables.
Recall the hypothesis from the example in
the previous slides was:
As a voter's income increases, he is more
likely to vote for a Republican than a Democrat.
If we were to collect data to provide support
for this hypothesis, or fail to provide support
for this hypothesis, we would have to collect
data on voter’s vote choices and their income.
We could use survey data to collect this information.
The last step in the scientific process is
evaluating our evidence from Step 4.
Did the data support our hypothesis?
Recall the hypothesis from the example in
the previous slides was:
As a voter's income increases, he is more
likely to vote for a Republican than a Democrat.
In order to analyze this relationship, I used
real data from the American National Election
Study from 2012.
Based on the results of the survey, the evidence
does support the hypothesis.
Low income voters are more likely to vote
for Democrats than Republicans.
69% of low income voters voted for Obama,
while only 50% of high income voters voted
for Obama.
In addition, high income voters are more likely
to vote for Republicans than Democrats.
Only 20% of low income voters voted for Romney,
while 50% of high income voters voted for
Romney.
Even if the evidence does support our hypothesis,
we should not overvalue evidence.
Before we draw definitive conclusions about
the relationship between an independent and
dependent variable, several studies need to
provide evidence of the relationship.
In addition, even if the evidence does not
support our hypothesis, that does not necessarily
mean that our independent variable does not
influence our dependent variable.
There could be several reasons why we get
null results, many of them mathematical.
But that is a topic that is covered in POLS
398.
Last, it is important to point out that in
this class, we will be focusing on developing
positive arguments, not normative arguments.
Positive arguments attempt to explain how
the world works.
Normative arguments attempt to explain how
the world SHOULD work.
For example, a positive argument could be:
Income affects vote choice.
Low income voters tend to vote for Democrats
while high income voters tend to vote for
Republicans.
These statements describe how the world works.
A normative argument could be: Income should
not affect vote choice.
Voters should vote based on the overall economic
performance of the entire country, not their
individual economic needs.
These statements describe how the world should
work.
