This document discusses key concepts in psychological measurement. It defines measurement and provides examples. A psychological construct is defined as a variable that is conceptualized but not directly observable, like intelligence. Constructs are measured using operational definitions that specify how the construct will be measured in practice. There are four levels of measurement: nominal, ordinal, interval, and ratio. Reliability ensures consistent measurement and validity ensures a measure actually measures the intended construct. Reliability is assessed over time, between items, and between raters. Validity includes face, content, criterion, and construct varieties. Proper measurement requires defining a construct, choosing a measure, implementing it carefully, and evaluating the reliability and validity.

1. PSYCHOLOGICAL
MEASUREMENT
Ch. 4

2. 19. Understanding Psychological
Measurement
•Learning Objectives
•Define measurement and give several examples of
measurement in psychology.
•Explain what a psychological construct is and give several
examples.
•Distinguish conceptual from operational definitions, give
examples of each, and create simple operational
definitions.
•Distinguish the four levels of measurement, give examples
of each, and explain why this distinction is important.

3. Measurement
•“the assignment of scores to individuals so that the scores
represent some characteristic of the individuals”
•Examples
•Using a scale to “measure” one’s weight
•Using a thermometer to “measure” the internal
temperature of a turkey roasting
•In Psychology, we can also refer to measurement as
Psychometrics
•Using a test to “measure” one’s working memory capacity

4. What Do We Measure in
Psychology?
•Constructs: variables we want to measure that are seemingly
not straightforward or simple to measure
•i.e., A concept we are trying to measure
•Must use a conceptual definition
• Describes the behavior and internal processes that
make up that construct, along with how it relates to
other variables

5. How Do We Measure It?
•Must use the operational definition
•A definition of the variable in terms of precisely how it will
be measured
•Types
•Self-report measure
•Behavioral measures
•Physiological measures

6. Levels (or Scales) of Measurement
•A variable can be measured on one of four scales:
•Nominal
•Ordinal
•Interval
•Ratio
•Important: Determines the type of statistics you can do and
conclusions you can make

7. Scales of Measurement for
Qualitative Data

8. Scales of Measurement for
Quantitative Data

9. Scales of Measurement Flow
Chart
Does the
scale involve
categories or
numbers?
Category
Can the
Categories be
ordered?
Numbers
Does the scale
have a true
zero point
(absence of
variable)?
Yes Ordinal
No Nominal
Yes Ratio
No Interval

10. Examples- Question 1
•If I wanted to see which table students are
more likely to approach at an organizational fair
(labeled Table 1, Table 2 & Table 3), what type
of scale would this be?

11. Examples- Question 2
•If I wanted to see which table students are
more likely to approach at an
organizational fair (the 1st from the right,
2nd, or 3rd), what type of scale would this
be?

12. Examples- Question 3
•What is Academic
Position?
•What about
Income?

13. Examples- Question 4
•Happiness Rating
(1-7)?
•# of people that
reported each
value?

14. Examples- Question 5
•Shirt Color?
•SAT Score?
•Range from 400-
1600

15. 20. Reliability and Validity of
Measurement
•Learning Objectives
•Define reliability, including the different types and how
they are assessed.
•Define validity, including the different types and how they
are assessed.
•Describe the kinds of evidence that would be relevant to
assessing the reliability and validity of a particular
measure.

16. Reliability vs. Validity
► Reliability: Ability to obtain consistent scores
► Validity: Ability of a test to measure what it’s supposed to
High Accuracy, Low Precision Low Accuracy, High Precision

17. Accuracy vs. Precision
Neither Valid
Reliable Valid & Reliable

18. Types of Reliability & Validity
Reliability Validity
Over time:
• Ability of a measure to be consistent
across multiple administrations
• Test-retest
Across items (internal):
• Ability of the same test to be consistent
throughout
• Split-half
Across different researchers:
• Ability for different people to measure
the same test consistently
• Inter-rater
Face Validity:
• How accurate something looks on the
surface
Content (Internal):
• The extent to which your test
accurately/actually measures the
behavior you are trying to measure
(conceptual definition)
Criterion Validity:
• Extent to which scores on a measure
correlate with other related variables
(as they should)
• Predictive or concurrent validity
• Convergent validity
Discriminant
• Extent to which scores on a measure
DO NOT correlate with other UNrelated
variables

19. Describe Reliability and Validity
► Scenario #1:
► The Morris Shoe-Size Intelligence Test
► IQ = shoe size x 10
► Scenario #2:
► You have 15 s to write as many t’s as you can
► Discuss the techniques you used to perform this
task
► Now, I’ll give you another 15s to repeat the task
Bolt, M. Instructor resources for Psychology retrieved from http://bcs.worthpublishers.com/WebPub/Psychology/myers11e/irm_pdf/myers11e_irm_ch10.pdf

20. 21. Practical Strategies for
Psychological Measurement
•Learning Objectives
•Specify the four broad steps in the measurement process.
•Explain how you would decide whether to use an existing
measure or create your own.
•Describe multiple strategies to identify and locate existing
measures of psychological constructs.
•Describe several general principles for creating new
measures and for implementing existing and new
measures.
•Create a simple plan for assessing the reliability and
validity of an existing or new measure.

21. Steps in the Measurement Process
•Conceptually define the Construct
•Decide on Operational Definition
•Using an existing measure
•Creating your own measure
•Implementing the Measure
•Caution: Look out for socially desirable responding and
demand characteristics
•Evaluating the Measure