This document discusses how to measure and define variables for research. It explains that variables can be either objectively or subjectively measured. An operational definition outlines how abstract concepts can be made measurable by specifying their dimensions and elements. Various scales are used to measure variables, including nominal, ordinal, interval, and ratio scales. Rating scales like Likert scales and ranking scales are scaling techniques to quantify responses. Reliability ensures stability of measures over time and internal consistency. Validity includes content, criterion-related, and construct validity to show a measure accurately evaluates what it intends to.

1. MEASUREMENT OF
VARIABLES:
OPERATIONAL
DEFINITION AND SCALES
CHAPTER 8

2. HOW VARIABLES ARE
MEASURED?
Two types of variables:
 Variable that lends itself to objective and precise
measurement
 Variable that doesn’t lend itself to accurate
measurement because of its subjective nature.
Abstract notions  observable characteristic
behavior  measurable in a tangible way 
called operationalizing the concepts
Operational definition is a statement of the
specific dimensions and elements through which a
concept will become measurable

3. OPERATIONAL DEFINITION: DIMENSIONS AND ELEMENTS

4. OPERATIONAL DEFINITION: DIMENSIONS AND
ELEMENTS

5. SCALES
Nominal Scales: splits data into groups, e.g., men, women
Ordinal Scales: ranks data in some order, e.g., exercising
for 20 minutes is good, for 30 minutes is better, for 40
minutes is best
Interval Scales: sets data on a continuum, e.g.
1 2 3 4 5
very low very high
Ratio Scales: starts with absolute zero and indicates
proportion, e.g.
0 5 10 ten is twice as big as five

7. MEASUREMENT:
SCALING,
RELIABILITY,
VALIDITY
CHAPTER 9

8. SCALING TECHNIQUES:
1. Rating Scales
Rating Scales
 Dichotomous Scales  yes or no answer
 Category Scales  uses multiple items to elicit a single
response
 Likert Scales  to examine how strongly subjects
agree or disagree with statement on a 5-point scale
 Semantic Differential Scales  several bipolar
attributes are identified at the extremes of the scale
 Numerical Scales  similar with Semantic Differential
Scales with number on 5 or 7 point scale are provided

9.  Itemized Rating Scales  a 5 or 7 point scale with
anchors is provided for each item and the respondent
state the appropriate number on the side of each item
 Fixed or Constant Sum Rating Scales  the
respondents are asked to distribute a given number of
points across various items, the sum is constant
 Stapel Scales  measure both direction and intensity
of the attitude toward the item under study
 Graphic Rating Scales  placing a mark at the
appropriate point on the line
SCALING TECHNIQUES:
1. Rating Scales…con’t

10. Ranking Scales
 Paired Comparisons  used when, among small
number of objects, respondents are asked to choose
between two objects at a time.
 Forced Choice  enables respondents to rank objects
relative to one another, among alternatives provided.
 Comparative Scales provides a benchmark or a point
of reference to assess attitude toward the current object,
event, or situation under study.
SCALING TECHNIQUES
2. Ranking Scales

11. GOODNESS OF MEASURES
Stability
 Test-retest reliability
 Parallel-form reliability
Internal Consistency
 Split-half reliability
 Interitem consistency reliability
Validity
Content Validity
 Face validity
Criterion-Related Validity
 Concurrent validity
 Predictive validity
Construct Validity