Introduction to Experimental Linguistics

2Building a Valid and Reliable Experiment

In Chapter 1, we reviewed the characteristics of an experimental study. We saw that carrying out an experiment comes down to manipulating at least one variable, in a controlled manner, in order to bring to light its effect(s) on one or more other variables. We also stressed the fact that each experiment should be used for testing a precise research hypothesis in which the observed variables are defined via an operationalization process. In this chapter, we discuss the different stages involved in the operationalization of a research question in detail. We see that the operationalization process requires making many choices as to the variables studied and the manner of measuring them and the conditions examined and the experimental design chosen. At the same time, these choices have consequences for the validity and reliability of the experiment. Thus, we begin this chapter with a presentation of the key concepts of validity and reliability. Secondly, we develop the notion of a variable introduced in the first chapter, in order to accurately define the types of variables involved in an experiment. Once this framework has been set, the rest of the chapter will deal with the stages for operationalizing a research question.

2.1. Validity and reliability of an experiment

In Chapter 1, we saw that the purpose of an experiment is to collect data in order to test a research hypothesis that states a cause-and-effect relationship between variables. ...