Requests for reprints should be sent to Ulrich Müeller, Department of Psychology, University of Victoria, P. O. Box 3050, STN CSC, Victoria, BC V8W 3P5, Canada, e-mail: emuelller@uvic.ca. JOURNAL OF APPLIED MEASUREMENT, 11(1), 78-90 Copyright © 2010 Thinking about Thinking— Thinking about Measurement: A Rasch Analysis of Recursive Thinking Ulrich Müeller University of Victoria Willis F. Overton Temple University Two studies were conducted to examine the dimensionality and hierarchical organization of a measure of recur- sive thinking. In Study 1, Rasch analysis supported the claim that the recursive thinking task measures a single underlying dimension. Item difﬁculty, however, appeared to be inﬂuenced not only by level of embeddedness but also by syntactic features. In Study 2, this hypothesis was tested by adding new items to the recursive thinking measure. Rasch analysis of the modiﬁed recursive thinking task produced evidence for the undimensionality and segmentation. However, Study 2 did not support the idea that syntactic features inﬂuence item difﬁculty.