Congruence in Research Question, Design, and Analysis: A Tutorial on the Measurement of Change in Clinical Speech and Language Research.

Purpose Measuring change is a common goal in clinical research, and comparing nonequivalent groups is sometimes a necessity in this context. Yet, evaluating change in this way can be problematic, and little consensus is reported on the best way to conduct such an evaluation. This tutorial presents the process of planning a clinical study designed to measure change in the context of a therapeutic intervention. Method This article presents a hypothetical clinical research scenario and follows the process of study design from question formulation to interpretation of results. The presentation focuses on the use of gain score analysis in the context of nonequivalent participant groups, methods that may be particularly relevant to the clinical context. Conditions that are favorable to gain score use, as well as situations that are problematic for gain score use, are presented. Conclusions In this article, the clinical research process is presented, following a logical process from formulation of a clear research question to selection of an appropriate research design to implementation of an effective analysis method. Gain score analysis is presented as an effective tool to measure change in clinical research, even with nonequivalent groups, given the correct conditions.