Statistics and the Logic of
Inquiry
Lecture 2
 Statistics
and theory
 Two
types of theory in political science: normative and
empirical
 Traditionally,
"political theory" was concerned with normative
matters  "political philosophy"
 1.Examples
of normative concepts: freedom, order,
equality
 2.Examples
of normative analysis: conflict between freedom and
order, between freedom and equality
 Statistical
analysis is concerned with empirical theory.
 Quantification
in general forces one to become more rigorous in
making statements
 Rigorous
theoretical thinking requires careful attention to
form and content of statements.
 Two
types of statements
 SINGULAR:
about particular thingsClinton is a
Democrat.
 GENERALIZATIONS:
Republicans are more conservative than
Democrats.
 Two
types of generalizations: Deterministic (E=mc2) and
probabilistic
 Statistical
analysis is concerned with testing the "truth value"
of probabilistic generalizations
 Statistics
is best suited for analysis of similar social
processes rather than unique events.
 Theoretical
assertions about these events must be explicit and
unequivocal  they must be
FALSIFIABLE.
 Science
advances more readily through error than
confusion.
 Two
types of statistics:
 DESCRIPTIVE
STATISTICS: describe and summarize data
 INFERENTIAL
STATISTICS:
 Generalize
beyond data at hand
 Evaluate
differences between groups
 Estimate
unknown values
 Our
course will be organized to take up descriptive
statistics first, then the more complex inferential
statistics
 Statistical
analysis should be tied closely to theory
construction.
 What is
an empirical theory?
 A
theory is a set of interrelated
propositions
 A
proposition is a statement of relationship
between concepts
 A
concept is a general idea for
grouping phenomena as similar
 Example:
politicoeconomic minitheory (from Bohrnstedt
and Knocke:Statistics for Social Data
Analysis)
 Propositions
P1:
Economic instability generates disaffection with the
national political regime
P2: Disaffection with the national regime strengthens
the opposition political forces
 Deduction:
P3:
Economic instability increases strength of political
opposition
 Theoretical
terms
 Scope
conditions:
 Units
of analysis:
 individuals,
 spatial
aggregates of individuals,
 organizations
 Testing
a theory
 Remember,
the goal is to render it FALSIFIABLE
 The
abstract concepts in the proposition must be made
concrete
 Done
through operationalization
 The
specified "operations" that must be performed to
measure the concept
 Often
multiple indicators of complex concepts are
desirable, but we will consider only single
indicators here.
 Example
of the politicoeconomic minitheory:
 Economic
instability > high inflation
rates
 disaffection
with national regime > negative attitudes
toward the president's economic policies
 strengthens
the opposition's political forces > increases
support for party not in the White House
 Adequacy
of operationalizations
 validity
 or accuracy
 reliability
 Causal
terminology for concepts or variables in a
theory
 Independent
variable  the causal agent
 Dependent
variable  the caused variable
 Graph
of the minitheory
 Propositional
form:
 ECONOMIC
DISAFFECTION WITH STRENGTHENING
 INSTABILITY
> NATIONAL REGIME >
OPPOSITION
 Hypothesis:
 HIGH
LOW PRESIDENTIAL VOTE AGAINST
 INFLATION
> POPULARITY >
INCUMBENT
