Author ORCID Identifier


Defense Date


Document Type


Degree Name

Doctor of Philosophy



First Advisor

Roy T. Sabo

Second Advisor

Robert A. Perera

Third Advisor

Nitai Mukhopadhyay

Fourth Advisor

Alex Krist

Fifth Advisor

Leroy Thacker


As researchers increasingly use web-based surveys, the ease of dropping out in the online setting is a growing issue in ensuring data quality. One theory is that dropout or attrition occurs in phases that can be generalized to phases of high dropout and phases of stable use. In order to detect these phases, several methods are explored. First, existing methods and user-specified thresholds are applied to survey data where significant changes in the dropout rate between two questions is interpreted as the start or end of a high dropout phase. Next, survey dropout is considered as a time-to-event outcome and tests within change-point hazard models are introduced. Performance of these change-point hazard models is compared. Finally, all methods are applied to survey data on patient cancer screening preferences, testing the null hypothesis of no phases of attrition (no change-points) against the alternative hypothesis that distinct attrition phases exist (at least one change-point).


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Available for download on Tuesday, April 07, 2020