Which type of reliability assesses if an assessment yields reliable results across its individual items?

The concept of internal consistency reliability pertains to the extent to which items within a single assessment or test yield consistent results. This type of reliability is crucial in evaluating whether different items that purport to measure the same underlying construct are generating similar responses.

For instance, if a standardized reading comprehension test includes multiple questions about the same passage, high internal consistency would suggest that responses to these questions are positively correlated, reflecting that the test effectively measures reading comprehension. A common statistic used to assess internal consistency is Cronbach's alpha, which calculates the average correlation among the items within the assessment.

In essence, internal consistency reliability helps ensure that an assessment is coherent and that the items within it work together to measure the same concept reliably, thereby providing confidence in the interpretation of the test scores.