Incremental validity principles in test construction.

The authors articulate 5 basic principles for enhancing incremental validity, both among elements within a test and between tests, during test construction: (a) careful, precise articulation of each element or facet within the content domain; (b) reliable measurement of each facet through use of multiple, alternate-form items; (c) examination of incremental validity at the facet level rather than the broad construct level; (d) use of items that represent single facets rather than combinations of facets; and (e) empirical examination of whether there is a broad construct or a combination of separate constructs. Using these principles, the authors offer specific suggestions for modifications in 3 classic test construction approaches; (a) criterion keying, (b) inductive test construction, and (c) deductive test construction. Implementation of these suggestions is likely to provide theoretical clarification and improved prediction.