1.10 Measurement Flashcards
#Measurement Process. Specification of observable referents for concepts of interest?
Concept/Construct (Conceptual definition) -> Variable (Operational definition)
Conceptual Definitions?
Self-esteem: A person’s overall evaluation of his/her own worth, value, or importance.
Social support: Aid, assistance, or support that is offered in a social relationship and intended to be helpful.
Operational Definitions?
-Procedures for assigning cases to values/categories of variables.
-Specifies the activities needed to measure the variable.
+How the data will be obtained
+What questions will be asked or observation will be made
+What the response categories are
+Any other instructions needed
Approaches to Operationalizing Measured Variables?
- Self-reports
- Observations
- Archival records
Composite Measures?
Measures that combine several indicators into a single index or scale.
Example: Rosenberg Self-Esteem Scale
Self-Esteem?
- Conceptual definition: A person’s overall evaluation of his/her own worth, value, or importance.
- Operational definition: Respondent’s self-report of self-esteem based on the Rosenberg Self-Esteem Scale (1965)
#Variables/ Level of Measurement?
- Nominal
- Ordinal
- Interval
- Ratio
Nominal?ex
- Values included 2 or more non-overlapping and exhaustive categories that have no mathematical relation to each other.
- Ex: gender; race/ethnicity; college major
Ordinal?ex
- Values indicate a rank ordering of the categories.
- Ex: social class (low, middle, high); Self-rated health status (very good, good, bad, very bad)
Interval?ex
- Values indicate categories that are ordered and separated by equal intervals, but there is no true zero.
- Ex: temperature (Fahrenheit); IQ
Ratio?ex
- Same properties as interval and there is an absolute (non-arbitrary) zero. All mathematical operations are possible.
- Ex: number years schooling; income (dollars)
Measurement Error?
Observed Value= True Value + Error
Observed Value= True Value + Systematic Error+ Random Error
Kind of Measurement Error?
- Systematic error
- Random error
Systematic error?ex
- Due to recurring, systematic factors.
- Error tends to lean in one direction.
- Causes systematic distortion (bias) in measurement
- Example: social desirability bias is the tendency of respondents to answer questions in a manner that will be viewed favorably by others. It can take the form of over-reporting good behavior or under-reporting bad behavior.
Random error?ex
- Due to chance factors
- Unrelated to true differences in the concept being measured.
- Error goes in all directions.
- Presence, direction, and extent are unpredictable
- Example: ambiguous items, fatigue
Judging the Adequacy/Goodness of Measurement?ex
-Reliability
Does the operational definition measure something with consistency and stability?
Is X always X?
-Validity
Does the operational definition measure what it is supposed to measure?
Is X really X?