Discovering learning styles to facilitate teaching and learning is always a critical issue in the field of education. Keefe (1979) defined learning styles as "characteristic cognitive, affective, and psychological behaviors that serve as relatively stable indicators of how learners perceive, interact with, and respond to the learning environment" (p. 4). Numerous studies have focused on this issue in various ways, and researchers have developed many instruments to classify learning styles. The Felder-Solomon Index of Learning Styles (ILS) is one of them. Since its publication in 1991, numerous researchers have investigated subjects related to it. Although the ILS was designed for engineering students, it has in fact been used to assess learning styles in many different disciplines and is gaining in popularity. According to Litzinger, Lee, Wise, and Felder (2005), since the online version of the ILS appeared, its site has received more than 100,000 visits per year, and many published studies have used the data.
Due to the obstacle of language, even though some Taiwanese scholars have translated the ILS into Chinese for their own classes or studies, it has never been officially introduced to Taiwanese students. For the current study permission was acquired from North Carolina State University to translate the ILS into Chinese and to use the data analysis to help Taiwanese college students learn and teachers teach. Because the ILS has never been tested by Taiwanese students on a large enough scale, and because of language and cultural barriers, the translated test items might not present the complete meaning of the original ILS to the testers. According to Felder (2002), the ILS "has been translated into half a dozen languages that I know about and probably more that I don't, even though it has not yet been validated" (p. 1). Therefore, the primary goals of the current study were to investigate the reliability and validity of the Chinese version of the ILS. In addition, various statistical analyses identified the problematic items for further modification.
THE INDEX OF LEARNING STYLES
Felder and Soloman developed the ILS to evaluate the learning style model formulated by Felder and Silverman in 1988 (Felder & Soloman, 2004). The Felder-Silverman learning style model defined four dimensions, each having two categories: perception (sensing/intuitive), input (visual/verbal), processing (active/reflective), and understanding (sequential/global). Learners should fit into one or the other category on each of the four dimensions. Thus, the Felder-Soloman ILS questionnaire consists of four parallel scales, with 11 items each, that are used to evaluate the four dimensions of the Felder-Silverman learning styles. Felder and Spurlin (2005) described the categories of the four dimensions as follows:
* sensing (concrete, practical, oriented toward facts and procedures) or intuitive (conceptual, innovative, oriented toward theories and underlying meanings)
* visual (prefer visual representations of presented material, such as pictures, diagrams, and flow charts) or verbal (prefer written and spoken explanations)
* active (learn by trying things out, enjoy working in groups) or reflective (learn by thinking things through, prefer working alone or with one or two familiar partners)
* sequential (linear thinking process, learn in incremental steps) or global (holistic thinking process, learn in large leaps)
Theoretically, all the dimensions are parallel, and a student's learning styles should be well distributed among the four dimensions. Each individual should have his or her own learning styles, and the ILS should be able to provide that personal information to students and instructors. Even though providing an individual student-centered approach is becoming a very popular practice in education, Felder and Brent (2005) pointed out, "If it is pointless to consider tailoring instruction to each individual student, it is equally misguided to imagine that a single one-size-fits-all approach to teaching can meet the needs of every student" (p. …