Transcript Concepts and Variables 8/30

Concepts and Variables
8/30/2012
Readings
• Chapter 1 The Measurement of Concepts (1423) (Pollock)
• Chapter 2 Measuring and Describing Variables
(Pollock) (pp.28-31)
OPPORTUNITIES TO DISCUSS
COURSE CONTENT
Office Hours For the Week
• When
– Friday 11-1
– Tuesday
– And by appointment
Course Learning Objectives
1. Students will learn the research methods
commonly used in behavioral sciences and
will be able to interpret and explain empirical
data.
2. Students will learn the basics of research
design and be able to critically analyze the
advantages and disadvantages of different
types of design.
The First Steps in Measurement
CONCEPTS
What are Concepts?
• Concepts are the words
we use to describe
political, social and
environmental
behaviors
• They name and
describe the external
world
The Conceptual Definition
• This is the conceptual definition takes abstract
things and make them real.
• States the concept in unambiguous terms
• Must communicate
– The variation within a concept
– The subject to which the concept applies
Types of Concepts
• Socio-economic
• Attitudinal
• Behavioral
• Environmental
The Operational Definition
• Turning your concept
into something that can
be measured
• Must be precise and
accurate
• This can be very difficult
The Operational Concept of Organic
The Concept of Poverty
Absolute Depravation
• The Federal Government
sets the poverty guidelines
• This is then used to
determine eligibility for
benefits
Relative Depravation
2012 Poverty Guidelines for the48 Contiguous States and the District of Columbia
Persons in
family/household
Poverty guideline
1
$11,170
2
15,130
3
19,090
4
23,050
5
27,010
6
30,970
7
34,930
8
38,890
For families/households with more than 8 persons,
add $3,960 for each additional person.
Definitions must match
When Concepts and Operations do not
match
Measurement
THE SECOND STEP: VARIABLES
What are Variables
• These are simply
measured concepts
• This is called
operationalization
• Good variables take on
all values of a concept
Variable measurement
• constants
• Dichotomous Variables
• The rest
The Dependent Variable
• The variable in a
relationship you want
to explain. The Y
variable
• There is only one of
these in a relationship
• It changes in response
to an independent
variable
The Independent variable
• Variables that that
cause change in the
dependent variable
• The (X) variable
• You may have more
than 1 of these
The Relationship Between them
Telling the Difference between I.V.’s
and the D.V.
Additive Relationships
• Most Social Science relationships involve
many i.v.’s…. Why?
• Explaining a Dependent variable with more
than 1 independent variable is called an
additive relationship!
Additive Relationships
Antecedent and Intervening Variables
Antecedent
• Come before the
independent variable
Intervening
• Come in-between the IV
and the DV
• Things like Demographics
• Temporal events
How they can influence relationships
A Spurious Relationship
• What antecedent variable might be at play?
How we measure our Variables
UNITS OF ANALYSIS
Units of analysis
• The unit about which information is collected
and that provides the basis of analysis
• Each member of a population is an element
• Why they are important?
Individual Unit
• The lowest form of data
• People, congressmen,
presidents, etc
Aggregate Data
• A collection of
individual level units
• Often measured in
percentages
• Footprints
The Poor over Time
Immigration over time
The Problem of Access
FALLACIES MADE WITH DATA
Ecological Fallacy
• this arises when an
aggregate/ecological level
phenomenon is used to
make inferences at the
individual level.
• Taking statewide data and
applying to individuals
• Does everyone in MS go
to church?
The Exception Fallacy
• taking one person's
behavior, attributes, etc
and applying it to an
entire group
• Using 1 example to
define group behavior
Examples from Texas Style