PS 235 Lecture NotesSpring 2010Clayton ThyneBased on Frankfort-Nachmias & Nachmias, Chapter 3

We recall from Ch.1 that social science is validated by (1) reason and (2) experience…or (1) the conceptual/theoretical and (2) the observational/empirical

Chapter 2 focused on #1: reason/theory

This chapter focuses on how you can go about testing your theory

We recall that scientific research must be empirically verifiable

This requires that we are specific about our hypothesized relationships

Scientific? How can we best promote democracy? How does state wealth impact the likelihood

of coups? Would McCain have reduced troops in Iraq? Should I support the health care bill?

Group A Group B

Mean = 51 Mean = 49.9

20%

got

95

80%

got

40

51%

got

45

49%

got

55

Mode = 51Mode = 40

Def – the most elementary part of what is to be studied

1st step in testing your theory Helps avoid..

Ecological fallacy – generalizing from groups to individuals

Individualist fallacy –generalizing from individuals to groups

We love

democracy

!

Nope

.

Your theory should culminate in a hypothesis, which is a tentative answer to your research question.

A hypothesis should… Be clear Be specific Be testable Be value-free

How we operationalize concepts Can be clearly identified and measured

ConceptsState wealthDemocracyEducationRegime stability

VariablesGDP/capitaPolity scores% literateYears since coup

Dependent (DV) = the concept to be explained Independent/explanatory (IV) =

induces/explains DV Y = f(X)

Plant growth = water + sun + soil Civil war onset = Education + GDP/capita + pop

Control variables (‘other’ IVs) Avoid omitted variable bias

Endogeneity issues …or does…education = civil war + GDP/capita +

pop?

Continuous = no minimum-sized unit (e.g., GDP/capita) Discrete = have a minimum size unit (e.g., rich/poor) H: Higher levels of democracy will lead to more state

wealth. Wealth (DV) = democracy (IV)

Continuous = income/capita

Discrete = Richer/poorer than median GDP/capita

Continuous = polity score

Discrete = democracy/non-democracy

H: Higher levels of democracy will lead to more state wealth.

Wealth (DV) = democracy (IV)Continuous = income/capitaDiscrete = Richer/poorer than median GDP/capita

Continuous = polity score Discrete = democracy/non-democracy

2.5

33.

54

4.5

gdpp

c

-10 -5 0 5 10polity2

| dem rich | 0 1 | Total-----------+----------------------+---------- 0 | 3,775 1,201 | 4,976 1 | 443 962 | 1,405 -----------+----------------------+---------- Total | 4,218 2,163 | 6,381 0

12

34

p 50

of g

dppc

0 1

-50

510

p 50

of p

olity

2

0 1

http://www.uky.edu/~clthyn2/PS235_GenEd/home.htm

…or ask Jason or me.