A researcher wants to determine internal consistency for the items on a personality assessment tool he has developed. Which of the following is true?
A) He must correlate different administrations of the same instrument
B) He can correlate two halves of the same test
C) He can compare the odd items with the even items
D) b and c

Question

Quizplus · Accepted Answer

To determine internal consistency, the researcher can use two methods:
1) Split-half method: the test is divided into two halves, and the scores on each half are compared using a correlation coefficient such as the Spearman-Brown formula to estimate the reliability of the full test.
2) Cronbach's alpha: it measures the extent to which all items on a test measure the same construct. The researcher can use this method by comparing the scores on each item with the scores on the other items, and calculating an alpha coefficient for the whole test.
Both the split-half method and Cronbach's alpha can be used by comparing odd and even items. Thus, the correct answer is D, as both b) (comparing two halves of the same test) and c) (comparing odd and even items) are viable options for measuring internal consistency.

A Researcher Wants to Determine Internal Consistency for the Items