One of the most effective approaches in facilitating second language learning is Content-Based Instruction (CBI). CBI is an approach to language acquisition using discipline content to deliver language instruction. Using CBI in college ESL courses has not only increased English Language proficiency, but has prepared students for traditional college courses by teaching them skills that promote success in those courses. Although previous studies have examined the use of CBI in the design of ESL classes and programs, little research has been done to examine the effect of using a CBI approach while implementing sustained themes across each level of a community college ESL program as it relates to the success, retention, and persistence rates of students within such a program. There is also a lack of research that examines the association between Sustained-Theme Content Based Instruction (STCBI) use and the wide variety of demographic characteristics that are represented in the post-secondary population. The purpose of this study was to investigate the association between the use of a STCBI approach in ESL and academic success of a diverse population of students preparing for college-level courses in an ESL program at a Southern California Community College. The strength of that association was determined by gathering and analyzing quantitative data concerning the academic success, retention, and persistence rates of the 416 students who took the English as a Second Language Placement Assessment and subsequently enrolled in the program during the four-semester period of fall 2010 through spring 2012.
