Chapter 4 Flashcards
What is measurement?
Measurement Is the assignment of scores to individuals so that the scores represent some characteristic of the individuals.
What is psychometrics?
A subfield of psychology concerned with the theories and techniques of psychological measurement.
One thing to keep in mind about measurement:
The important point here is that measurement does not require any particular instruments or procedures. What it does require is some systematic procedure for assigning scores to individuals or objects so that those scores represent the characteristic of interest.
What is a construct?
Psychological variables that represent an individual’s mental state or experience, often not directly observable, such as personality traits, emotional states, attitudes, and abilities.
Why can’t psychological constructs be observed directly?
They represent tendencies to think feel or act in certain ways.
What are the BIG 5?
A set of five broad dimensions that capture much of the variation in human personality. Each of the big five can even be defined in terms of six more specific constructs called “facets” (Costa & McCrae, 1992).
BIG 5
Openness to Experience
Conscientiousness
Extroversion
Agreeableness
Neuroticism
What is a conceptual definition?
Describes the behaviors and internal processes that make up a psychological construct, along with how it relates to other variables.
What is an operational definition?
A definition of the variable in terms of precisely how it is to be measured.
What are the 3 categories of operational definitions?
Self-report measures: Measures in which participants report on their own thoughts, feelings, and actions.
Behavior measures: Measures in which some other aspect of participants’ behavior is observed and recorded.
Physiological measures: Measures that involve recording any of a wide variety of physiological processes, including heart rate and blood pressure, galvanic skin response, hormone levels, and electrical activity and blood flow in the brain.
What are converging operations?
When psychologists use multiple operational definitions of the same construct—either within a study or across studies.
Who suggested 4 scales of measurement?
The psychologist S. S. Stevens suggested that scores can be assigned to individuals in a way that communicates more or less quantitative information about the variable of interest (Stevens, 1946).
Stevens actually suggested four different levels of measurement (which he called “scales of measurement”) that correspond to four types of information that can be communicated by a set of scores, and the statistical procedures that can be used with the information.
What are the 4 levels of measurement?
Nominal
Ordinal
Interval
Ratio
Nominal Level of Measurement:
A measurement used for categorical variables and involves assigning scores that are category labels.
The essential point about nominal scales is that they do not imply any ordering among the responses. For example, when classifying people according to their favorite color, there is no sense in which green is placed “ahead of” blue. Responses are merely categorized. Nominal scales thus embody the lowest level of measurement.
Ordinal Level of Measurement
Pro: The ordinal level of measurement involves assigning scores so that they represent the rank order of the individuals.
Con: On the other hand, ordinal scales fail to capture important information that will be present in the other levels of measurement we examine. In particular, the difference between two levels of an ordinal scale cannot be assumed to be the same as the difference between two other levels (just like you cannot assume that the gap between the runners in first and second place is equal to the gap between the runners in second and third place).
Statisticians express this point by saying that the differences between adjacent scale values do not necessarily represent equal intervals on the underlying scale giving rise to the measurements.