Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Graduation


Document Type


Degree Name

Doctor of Philosophy (PhD)


Department of Graduate Psychology


Brian C. Leventhal

Christine DeMars

Dena Pastor


Likert items are the most commonly used item-type for measuring attitudes and beliefs. However, responses from Likert items are often plagued with construct-irrelevant variance due to response style behavior. In other words, variability from Likert-item scores can be parsed into: 1) variance pertinent to the construct or trait of interest, and 2) variance irrelevant to the construct or trait of interest. Multidimensional Item Response Theory (MIRT) is an increasingly common modeling approach to parse out information regarding the response style traits and the trait of interest. These MIRT approaches are categorized into threshold-based approaches and response process approaches. An increasingly common response process approach is the IRTree family of models. Often, researchers describe IRTree models as superior to other MIRT methods (e.g., threshold based approaches). However, IRTree models assume a particular response process. I investigate the effects of assuming an incorrect response process on person trait recovery, specifically on the recovery of the trait of interest. I conducted a 4-factor simulation study to investigate the effects of assuming an incorrect response process on person trait recovery, where the factors were the assumed response process, the true response process, correlations between traits, and scale length. The results indicated that assuming an incorrect response process does impact person trait recovery. In some conditions, the effect of assuming an incorrect response process on trait recovery depends on other factors such as scale length. Furthermore, the results indicate that the response process models had better person trait recovery compared to a threshold-based model, even when the response process model was incorrectly specified.



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