Class 3 - Theory and Hypotheses

8/7/2019 Class 3 - Theory and Hypotheses

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Theory/HypothesesFirst Steps in the Scientific Process


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The Scientific Process

Research Question

Theory and Hypotheses

Research Design

Operationalization (measurement) Empirical Observation and Analysis

Deductive Explanation: the process of reasoning from

general theory to specific observationsScientific Explanation: Effort to understand the world(explain various phenomena) by systematicallyexamining causalrelationships among variables


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The Research Question

Subject to empirical investigation

Avoid normative questions

normative: value-laden, evaluative, ought or

should, prescriptive Non-normative: factual, objective

Avoid purely factual questions.

E.g. How many seats did the Republicans gain in

Congress during the last election? Ask questions which can be answered in causal terms

(why questions)

Remember: causal relationships


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Is negative advertising bad for the political process?

Did candidates use negative advertising during the last

election?

Did negative advertising suppress voter turnout during last

years congressional elections?

Does the use of negative advertising suppress voter turnout in

elections?

Developing a Research

Question


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Research Question Assignment

1. State the research question in question form, according to

the guidelines discussed in class.

2. Explain what is meant by the basic concepts used in the

research question.

3. Be a salesman: tell me why this research question isimportant to study, why it is original, why it has not been

adequately explored in the past, etc..

4. Propose a research question. You do not have to propose

an answer to the question.

Note: try to be original, but logical.


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What is a Theory?

Tell me a story.

A set of assumptions and/or propositions involving a set of

interrelated concepts from which a causal statement(s) can be

derived. These assumptions and causal statement(s)constitute an explanation for the phenomenon under

investigation.

Every argument involves assumptions; make them explicit.

A reasoned and precise speculation about the answer to a

research question, including a statement about why the

proposed answer is correct.

Must have observable implications.


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Concepts:

Building Blocks of Theory

Concepts are words/terms that are the building blocks

of theories

Def: A concept is an abstraction representing an object,

a property of an object, or a certain phenomenon.

Examples: socioeconomic status, party competition,

welfare generosity


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Simple Theory: Example

What is the Effect of Negative Advertising on Political Participation?

Higher levels of exposure to negative advertising lead to lower

levels ofpolitical trustbecause voters gradually become

disenchanted with all political candidates. As trust is eroded, we

should expect to see lower levels ofpolitical participation.


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Class Exercise

Conceptually define this term:

Political Participation


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Hypotheses

A hypothesis is a testable statement of causal relationship

between two variables, derived from theory.

Observable Implications of theory

Relationships expressed in hypotheses may be either positive or

negative.

What do these terms mean?


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Concepts v. Variables

Hypotheses begin the move from concepts (found in theory) to anoperationalization of variables that can be observed and tested.

Concept

Highly abstract

Can represent a variety of things

Variable

Generally more specific/observable

Takes on at least 2 values/categories that vary across the units/cases

in our analysis Causal relationship: change in one variable causes a change in

another.

Operationalization and measurement of variables to be disucssedlater.


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Types of variables

Dependent variable : phenomena impacted by the explanatory variable.

what we are trying to explain

Independent/explanatory variable: measurements of phenomenon that

are thought to influence or cause changes in the dependent variable.

Control variables: other causal factors that may influence the dependent

variable.

More to be discussed later

Qualitative v. Quantitative Research

Another way to define a hypothesis: explicit statement as to how one

thinks variables are related.


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Good Hypotheses

Are the logical implications of the theory being tested

Are stated in explicit, empirical terms

Can be generalized to different contexts

Are plausible

Clearly specify a relationship between an IV & DV


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Directional Hypotheses

Apply to cases where IV and DV are orderable (directional)variables.

Positive relationship:

As ones education increases, the probability of voting increases

There is a positive relationship between ones education level andvoting

Negative or Inverse relationship:

As the number of hours of negative ads watched increases, theprobability that an individual will vote decreases

There is a negative relationship between exposure to negativeadvertising and the probability that an individual will vote


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Non-Directional Hypotheses

Appropriate for variables that are not orderable

Hypothesis describes comparison among categories

Examples:

Men have greater levels of support for President Bush than

do women

Whites are most likely to be Republican, while African-

Americans are most likely to be Democrat


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The Null Hypothesis

The null hypothesis states that there is no relationship

between the independent variable and the dependent

variable

Hypothesis: There is a positive relationship between

exposure to negative ads and turnout

Null hypothesis: There is no relationship between negative

ads and turnout


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Some Important Theories in Political Science

The Calculus of Voting (Why do people participate in

elections?)

Median Voter Theory (What explains variation in the policy

positions taken by political parties/candidates?)


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The Calculus of Voting:

HypothesesHypotheses Observable Implications of Theory:

Voter Turnout will increase as:

As the perceived support for each candidate equalizes

When perceived ideological distance between candidates increases

As the requirements for voter registration become easier

As levels of voter attachment to the political system increases (trust,

efficacy)


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Median Voter Theory

Key Assumptions/Building Blocks of Theory:

Voter preferences can be summarized as falling somewhere

on a liberal-conservative (left-right) ideological scale

In a 2-party system, voters choose the party that most closely

reflects their policy preferences

Parties are solely motivated to win elections


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Median Voter Theory


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Median Voter Theory:

HypothesesHypotheses - Observable Implications of Theory:

In a 2-party system, a positive relationship exists between the

extent to which a party appeals to the median voter and itslikelihood of success in an election.


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Unit of Analysis

The types or levels of political actor to which the hypothesis isthought to apply (JRM 77)

The social entities whose characteristics are the focus of the study.

Examples:

The more affluent a country, the more likely it is to have democraticpolitical institutions.

Northwestern cities are more likely to have mayors, while westerncities are more likely to have city managers.

The Supreme Court is more likely to grant cert. to cases implicating acircuit split.

A Supreme Court justice is more likely to vote to grant cert. if he/shedisagrees with the lower courts decision.

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Class 3 - Theory and Hypotheses

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