Using Funnel Items and Irtrees to Evaluate Response Style Effects between Different Item Formats

This study evaluated the effect of Likert item and funnel item formats on extreme response style (ERS) and midpoint response style (MRS) tendencies in respondents. Item formats were implemented using a 5-point and 7-point response scale. Items were modeled using a fully dichotomous (5-point) or partially dichotomous IRTree (7-point).