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Questions and Answers
What does construct validity primarily assess?
What does construct validity primarily assess?
Which type of validity is concerned with whether a measure correlates with other measures of the same construct?
Which type of validity is concerned with whether a measure correlates with other measures of the same construct?
In Classical Test Theory, what primarily causes the discrepancy between the test score and the true score?
In Classical Test Theory, what primarily causes the discrepancy between the test score and the true score?
What does concurrent criterion validity measure?
What does concurrent criterion validity measure?
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What is a characteristic of a true score in Classical Test Theory?
What is a characteristic of a true score in Classical Test Theory?
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What does local independence signify in the context of latent variable modeling?
What does local independence signify in the context of latent variable modeling?
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Which framework is specifically designed for binary indicators in tests?
Which framework is specifically designed for binary indicators in tests?
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What is one main benefit of latent variable modeling compared to traditional methods?
What is one main benefit of latent variable modeling compared to traditional methods?
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In Structural Equation Modelling (SEM), what specifically does factor analysis represent?
In Structural Equation Modelling (SEM), what specifically does factor analysis represent?
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What characterizes formative constructs in modelling?
What characterizes formative constructs in modelling?
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What does Test-Retest Reliability measure?
What does Test-Retest Reliability measure?
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What is one potential issue with Test-Retest Reliability?
What is one potential issue with Test-Retest Reliability?
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What is the purpose of the Spearman-Brown formula?
What is the purpose of the Spearman-Brown formula?
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What does Cronbach’s Alpha assess?
What does Cronbach’s Alpha assess?
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What is a key characteristic of latent variables in modern psychometrics?
What is a key characteristic of latent variables in modern psychometrics?
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How many observed variables are needed to model a latent variable effectively?
How many observed variables are needed to model a latent variable effectively?
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In Split-Half Reliability, what method is used to correlate the two halves of the test?
In Split-Half Reliability, what method is used to correlate the two halves of the test?
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What assumption does the internal consistency method rely on?
What assumption does the internal consistency method rely on?
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Study Notes
Psychometrics
- Psychometrics is the science of measuring psychological constructs
- Examples of psychological constructs include personality traits, cognitive skills, ability, and psychopathological disorders
- Examples of measuring depression are questionnaires such as the Beck Depression Inventory (BDI)
Measurement of Depression
- A depression inventory (e.g., BDI) uses items to measure constructs, such as hopelessness
- Example items include questions about feelings of hopelessness and concentration difficulties
- BDI questions include statements like "I am not particularly discouraged about the future" or "I can't do any work at all."
Construct Validity
- Construct validity is the extent to which a measure accurately measures what it claims to measure
- Two subjective methods include face validity (does the measure look like what it measures) and content validity (does the measure include all aspects of the construct)
- Empirical methods include criterion validity, convergent validity, and discriminant validity
Criterion Validity
- Concurrent criterion validity checks if a measure correlates with a relevant behavior at the same time
- Predictive criterion validity checks if a measure correlates with a relevant behavior at a different time
Convergent Validity
- Convergent validity checks if a measure correlates with other measures of the same construct
Discriminant Validity
- Discriminant validity checks if a measure does not correlate with measures of other constructs
Classical Test Theory (CTT)
- CTT frames test scores as the sum of a true score and an error score
- X=T+E, where X is the test score, T is the true score, and E is the error score
- A true score is the average score a person would get if they took the same test repeatedly in the same conditions.
Reliability
- Reliability is how consistent a test is in its measurement
- Reliability is the proportion of variance in the test score due to the true score
- Reliability is the squared correlation between a test score and a true score
- Acceptable levels for reliability include >0.7 for early research, >0.8 for applied research, and >0.9 for making important decisions.
- Reliability estimation methods include parallel tests, test-retest, and split-half reliability.
Internal Consistency Reliability (e.g., Cronbach's Alpha)
- Internal consistency assesses the extent to which items on a test correlate with each other. Cronbach's alpha is a commonly used measure of internal consistency.
- Values close to 1.0 indicate items are very highly correlated (redundant). A value of 0.8 is frequently considered desirable.
Modern Psychometrics
- Modern psychometrics uses latent variable models, where a latent variable (e.g., depression) is not directly observed but inferred from observed variables (items on a questionnaire).
- These models can account for relationships between observed variables, making inferences about the latent variable more accurate.
Latent Variable Modeling
- Key assumptions for latent variable models in psychometrics are local independence and unidimensionality.
- Local Independence - the unobserved variable explains all correlations between observed variables
- Unidimensionality - only one latent variable underlies all indicators/items.
Item Response Theory (IRT)
- IRT models the probability of a correct response on an item, given a person's ability level.
- It’s used for exams, educational tests, etc. and allows modeling item difficulty and discrimination between different ability levels. This contrasts with CTT which typically examines the total score.
Factor Analysis
- Factor analysis is a technique to analyze interrelationships among a set of items to identify latent variables (factors) that underlie observed variable scores. It assumes the observed variables are correlated due to their connection to shared latent factors (e.g., depression)
Structural Equation Modelling (SEM)
- SEM allows for modeling causal relationships between latent variables
- Factor analysis is a specific example of structural equation modeling
- Formative latent variables—the indicators themselves define the latent variable (e.g., socioeconomic status (SES), determined by income, occupation, and education)
- Reflective latent variables—the latent variable causes the indicators.
Network Psychometrics
- Network psychometrics sees psychological constructs as networks of interacting components
- This approach examines the unique interactions between observed variables, focusing on the network structure rather than the latent variables.
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Description
Test your knowledge on key concepts in psychometrics, focusing on various types of validity, including construct validity and concurrent criterion validity. This quiz also explores Classical Test Theory and its distinctions between test scores and true scores. It's an essential quiz for anyone studying measurement in psychology and education.
