Reliability/Item Analysis Button

Click the button to display the Reliability and Item Analysis (Startup Panel). Reliability and Item Analysis can be used to construct reliable measurement scales, to improve existing scales, and to evaluate the reliability of scales already in use. Specifically, reliability and item analysis techniques aid in the design and evaluation of sum scales, that is, scales that are made up of multiple individual measurements (e.g., different items, repeated measurements, different measurement devices, etc.).

The Reliability and Item Analysis module includes a comprehensive selection of procedures for the development and evaluation of surveys and questionnaires. You can calculate reliability statistics for all items in a scale, interactively select subsets, or obtain comparisons between subsets of items via the "split-half" (or split-part) method. In a single run, you can evaluate the reliability of a sum-scale as well as subscales. When interactively deleting items, the new reliability is computed instantly without processing the data file again. The output includes correlation matrices and descriptive statistics for items, Cronbach Alpha, the standardized Alpha, the average inter-item correlation, the complete ANOVA table for the scale, the complete set of item-total statistics (including multiple item-total R's), the split-half reliability, and the correlation between the two halves corrected for attenuation.