Experimental and quasi-experimental designs

Abstract

Researchers within the field of applied linguistics have long used experiments to investigate cause-effect relationships regarding the use and learning of second languages (L2s). In experimental research, one or more variables are altered and the effects of this change on another variable are examined. This change or experimental manipulation is usually referred to as the treatment. Researchers typically draw upon either experimental or quasi-experimental research designs to determine whether there is a causal relationship between the treatment and the outcome. This chapter outlines key features and provides examples of common experimental and quasi-experimental research designs. We also make recommendations for how experimental designs might best be applied and utilized within applied linguistics research.