Concordancers are software programs that allow users to search for all occurrences of a word or sequences of words. Early descriptions of the potential for student concordancing were given by Tim Johns, who called it Data Driven Learning (DDL). Johns (1991) explains DDL as an investigation allowing students to form their own questions about the language, ask for authentic language samples via a concordancer, and use those language samples to help them find an answer to their question. DDL relies on the students to form their own generalizations about the language once they are presented with samples of the target language. The authors conducted a small case study to investigate how English as a Second Language (ESL) students with little prior training could do with a concordancer when correcting grammar errors. In this article, they first provide some background information about student use of concordancers. Then they describe the methods and results of the study, and discuss suggestions for future research and how to teach concordancing to students.