Measurement Flashcards
Measurement
Assignment of scores to individuals so that the scores represent some characteristic of the individuals
Psychometrics
General definition of measurement in psychology
Conceptual definition
Psychological construct describes the behaviours and internal processes that up that construct, along with how it relates to other variables
Operational Definition
Definition of a variable in terms of precisely how is is to be measured
Self report measures
Are those in which participants report their own thoughts, feelings, and actions
Behavioural measures
Are those in which some other aspect of participants behaviour is observed and recorded
Physiological measures
Measuring of physiological processes like heart rate, respiratory rate
Converging Operations
Multiple operational definitions coming together
Levels of measurement
There are 4 of them
Nominal
Ordinal
Interval
Ratio
Nominal Level
Measurement is used for categorical variables and involves assigning scores that are category labels
The measurement process
Constructs, definitions, measures
Levels of variables
Nominal
Ordinal
Interval
Ratio
What is German mathematician carl Friedrich gauss say
- Knowledge and Chance
- Chance “the enemy of all knowledge, overcome”
Louis Agassiz
zoologist: Classify humans by moral + physical traits
Measurement
Giving numerical value to some phenomenon
“Constructs”
Measure tendencies over time that are not directly observable. can be complex, can consist of personality
Qualitative meaurements
Example of constructs
Extraversion = outgoing, enjoy social interactions
Conceptual Definition
may describe behaviours and internal processes making up that construct
More variable
Operational Definitions
Defining how to precisely measure a construct
More specific
Example of operational definitions
Self report measures: report on own thoughts, feelings, actions
Behavioural measures
Alternative approach to avoid the subjective nature of questionnaires: measure participants responses that are produced automatically
Physiological measures
Recording measures such as heart rate, blood pressure, cortisol levels
2 conditions of categorical variables
- Categories are mutually exclusive
- Categories must be collectively exhaustive
Discrete variable
the answer is constrained to be a whole number, can’t take on any value between the whole number
Continuous variable
Can assume any reasonable value
Nominal measurement
Yes/No answers
Ordinal measurement
you know the order but not the distances/intervals between the categories. You cannot add or subtract
Example of Ordinal measurement
Linkert scale
interval measurement
Distances/intervals are the same between the values. But no true 0
Ratio measurements
Most precise, ranging from an absolute 0 to infinity
Phase 1 of Scale Development
Item Development
1. Identification of Domain and item generation
2. Content validity
Phase 2 of Scale Development
Pre testing of questions
Sampling and survey administration
Item reduction
Understanding how many factors the scale captures `
Phase 3 is scale evaluation
Tests of the number of dimensions
Tests of reliability is tested
Tests of validity
Reliability
A scale’s ability to produce consistent results over time under consistent conditions
Reliability coefficient
0 to 1
Reliability coefficient is effected by
Random error
How can reliability can be determined
Over time
Across different researchers
Parallel forms of reliability
Internal consistency
Content validity
Does a scale measure what it is supposed to measure
Face validity
Extent to which a scale measures a construct on its face
Criterion validity
Extent to which scored on a measure are correlated with other variables
Discrimant validity
Extent to which variables that are not related to each other should show different scores
Feasibility
An assessment of the practicality of a proposed project/plan/scale
