Combining diverse methods in a single study raises a problem: What should be done when the findings of one method of investigation conflict with those of another? We illustrate this problem using an example in which three study phases--quantitative, qualitative, and intervention--were applied. The findings coming from the quantitative phase did…

Combining diverse methods in a single study raises a problem: What should be done when the findings of one method of investigation conflict with those of another? The authors illustrate this problem using an example in which three study phases--quantitative, qualitative, and intervention--are applied. The findings from the quantitative phase did…

Geometric approaches to representing interrelations among tests and items are compared with an additive tree model (ATM), using 2,644 examinees and 2 other data sets. The ATM's close fit to the data and its coherence of presentation indicate that it is the best means of representing tests and items. (TJH)