Washback or backwash, a term now commonly used in applied linguistics, refers to the influence of testing on teaching and learning (Alderson & Wall, 1993), and has become an increasingly prevalent and prominent phenomenon in education-“what is assessed becomes what is valued, which becomes what is taught” (McEwen, 1995a, p. 42). There seems to be at least two major types or areas of washback or backwash studies-those relating to traditional, multiple-choice, large-scale tests, which are perceived to have had mainly negative influences on the quality of teaching and learning (Madaus & Kellaghan, 1992; Nolan, Haladyna, & Haas, 1992; Shepard, 1990), and those studies where a specific test or examination1 has been modified and improved upon (e.g., performance-based assessment), in order to exert a positive influence on teaching and learning (Linn & Herman, 1997; Sanders & Horn, 1995). The second type of studies has shown, however, positive, negative, or no influence on teaching and learning. Furthermore, many of those studies have turned to focus on understanding the mechanism of how washback or backwash is used to change teaching and learning (Cheng, 1998a; Wall, 1999).