ABSTRACT
This chapter explains how students run an item analysis in SPSS to verify the homogeneity of scores. The result of the item analysis, however, is not only a figure indicating the degree of homogeneity. Students can also determine which items are and are not adequate by computing the item-total correlation. The ‘Alpha if Item Deleted’ column indicates that the homogeneity would become 0.74 if RHAP2 were to be removed from the list. The homogeneity would rise considerably as a result. On the basis of previously mentioned criteria, an alpha reliability index of 0.83 is said to be rather high, especially when such a small number of items is involved. In calculating the homogeneity, students must certainly be aware of the fact that a scale’s homogeneity is higher when it contains more items. If they have a large number of items the homogeneity can be quite high despite relatively low item-total correlations.
