Question 5: In what sense can Cronbach’s alpha and test-retest reliability indicate that factors are highly reliable?
Cronbach’s alpha measures the extent to which the factor is internally consistent, i.e. the average correlation between the variables which make it up and the correlation between the measured variable (the sum of the scores) and the latent variable which the factor represents. The higher alpha is, the greater the internal consistency. This is one aspect of the reliability of a scale.
Test-retest reliability measures the extend to which when the scale is remeasured we get the same answer, usually the correlation between the score collected on two separate occasions. This is another aspect of the reliability of a scale.
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Last updated: 5 March, 2007.