assumptions for assessing internal consistency among
errors are not correlated with each
errors not correlated with true scores
latent variables affect all items equally
amount of error for each item is equal
classical assumptions are relaxed in what's called
"Tau-equivalent" tests (tau stands for T as in true
more liberal assumption is that the amount of error
variance associated with a given item need not equal
the error variance.
last condition above of "equal errors" for each item
means that item means and variances may also
classical assumptions for scale reliability in the internal
- The greater the intercorrelations
among the items, the more reliable the scale.
- The greater the number of items, the
more reliable the scale.
- For practical research
applications, one seeks
- A scale of few items with high
intercorrelations to produce reliable
- A metric that can express the
degree of reliability.