Psychometrics: Reliability in Testing

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is measured by test-retest reliability?

The average performance of individuals on a single test

The correlation between two scores from different individuals

The variation in test scores among a group of individuals

The consistency of the same person's scores on two occasions (correct)

What is the recommended interval for conducting a test-retest to ensure reliability?

Exactly 3 months

Usually 1 week

At least 1 month

No more than 6 months (correct)

What does the coefficient of equivalence assess?

The correlation of scores from two different individuals

The reliability of a single test

The variation in scores across different testing conditions

The reliability between two equivalent forms of a test (correct)

Which of the following formulas is used to adjust the half-test reliability correlation coefficient?

Spearman-Brown formula Signup and view all the answers

What does internal consistency reliability evaluate?

Consistency between different items on a test Signup and view all the answers

In parallel-forms reliability, what is necessary for the two test forms?

They should have equal difficulty levels Signup and view all the answers

Split-half reliability provides insight into which aspect of reliability?

Consistency across equivalent halves of a test Signup and view all the answers

What is the primary focus of alternate-forms reliability?

The impact of item sampling error on test scores Signup and view all the answers

What formula is recommended when the standard deviations of the half-tests are not the same?

Rulon-Flanagan Formula Signup and view all the answers

Which reliability method is most commonly used when there is a right or wrong answer?

Kuder-Richardson (KR20) Signup and view all the answers

Which formula does not require real equivalency of both halves?

Guttman Formula Signup and view all the answers

What is the impact of higher homogeneity of the behavioral domain on inter-item consistency?

It increases the consistency Signup and view all the answers

What type of reliability approach is expressed with Cohen's Kappa?

Inter-Scorer Reliability Signup and view all the answers

When should test-retest or alternate forms be used?

In static contexts Signup and view all the answers

Which statement about a restricted range in reliability is accurate?

It typically produces lower reliability scores Signup and view all the answers

What does the Coefficient Alpha measure in assessment tools?

Inter-Item Consistency Signup and view all the answers

Which type of measurement error is characterized by predictable fluctuations?

Systematic Error Signup and view all the answers

In Classical Test Theory, which formula represents the relationship between obtained score, true variance, and measurement error?

X = T + e Signup and view all the answers

What does the concept of reliability refer to in the context of test scores?

The consistency and freedom from measurement errors of test scores Signup and view all the answers

Which factor contributes to error variance in test scores?

The method of test administration Signup and view all the answers

What is the primary purpose of a reliability coefficient in psychological testing?

To evaluate the consistency of test scores Signup and view all the answers

In which reliability type are identical tests administered twice to assess score stability?

Test-retest reliability Signup and view all the answers

What does the standard error of measurement assess in terms of reliability?

The estimated deviation of obtained scores from the true score Signup and view all the answers

Which of the following factors is NOT considered an intrinsic source of measurement error?

Test-taker emotional state Signup and view all the answers

Study Notes

Reliability

Reliability describes the consistency and freedom from measurement errors in test scores.
Measurement error refers to any fluctuations in scores that occur due to factors other than the actual trait being measured.

Sources of Measurement Error

Intrinsic Error Variance: Errors arising from the test itself, such as poor test construction or inappropriate item selection.
Extrinsic Error Variance: Errors that occur outside the test, such as variations in test administration, test-taker variables (e.g., mood, motivation), or examiner influence.

Classical Test Theory

Also known as the theory of true and error scores.
The theory suggests that test scores are a combination of true variance (the actual trait being measured) and error variance (random fluctuations).
Formula: X = T + e (Obtained Score = True Variance + Error)

Methods of Estimating Reliability

Reliability Coefficient: A correlation coefficient that measures the consistency between two sets of scores.
Standard Error of Measurement: A measure of the estimated deviation of obtained scores from the true score.

Types of Reliability

Temporal Stability: How consistent test scores are over time.
- Test-Retest Reliability: Measures the correlation between scores on the same test administered on two different occasions.
- Alternate-Forms Reliability: Measures the correlation between scores on two different versions of the same test.
Internal Consistency: Measures the consistency of items within the test.
- Split-Half Reliability: Divides the test into two halves and measures the correlation between the scores on each half.
- Kuder-Richardson (KR20) and Alpha Coefficient: Measures the inter-item consistency within a test. Used when there are right or wrong answers (KR20) or when there are no right or wrong answers (Alpha).
- Inter-Scorer/Inter-Rater Reliability: Measures the consistency of scoring between different raters or scorers, particularly for tests with subjective scoring.

Factors Affecting Reliability

Homogeneity: The extent to which test items measure the same construct. Higher homogeneity generally leads to higher reliability.
Heterogeneity: The extent to which test items measure different constructs. Lower homogeneity leads to lower reliability.
Dynamic vs. Static Traits: Dynamic traits (e.g., mood) are more susceptible to change over time, requiring different types of reliability measures (e.g., internal consistency). Static traits (e.g., intelligence), which are less variable, are more suitable for measures of temporal stability.
Restricted Range: A narrow range of scores can lead to lower reliability as the variability in scores is limited.
Inflated Range: A wider range of scores can lead to higher reliability as there is more potential for variability.

Interpreting Reliability Coefficients

Higher reliability coefficients (closer to 1.0) indicate greater consistency and less error.
The acceptable range of reliability depends on the purpose of the test (research, clinical use) and the type of reliability assessed.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz explores the concept of reliability in psychometrics, focusing on measurement errors and their sources. Understand intrinsic and extrinsic error variances and the Classical Test Theory that explains how true scores and error scores interact. Test your knowledge on estimating reliability coefficients and their significance.