An Advanced Course in Communication Sciences and Disorders

Research Importance and Statistical Significance

Statistics are the numerical procedures for analyzing and summarizing quantitative data. Statistical analyses are used to determine the significance of research and its power to generalize beyond the sample from which the data were derived. A finding is considered statistically significant if the null hypothesis is rejected. In statistics, a significant result suggests the probability that the findings are not due to chance. Significance, when used in statistics, does not refer to the importance of the study. Not all statistically significant research is important research.

The power of a study to explain some dimension or aspect of communication sciences and disorders is related to the fundamental importance of the hypothesis (or research question) and the research design. Simply finding a statistically significant correlation or difference between two or more variables or groups does not define the importance of the study. For example, it may be statistically significant that males and females with global aphasia differ in their response time during confrontational naming tasks. The data and inferential statistics may provide a strong confidence level that males with aphasia respond more slowly during picture naming tasks than do their female counterparts, no matter the success of naming. In this hypothetical example, although this discovered fact does cast light on the general nature of global aphasic patients' confrontational naming behaviors, and thus contributes to the general body of information in clinical aphasiology, it is of little practical importance. It does not give the clinician meaningful diagnostic or therapeutic information and improve the quality of services provided to patients with aphasia. Conversely, a study addressing the relative success rates of confrontational naming strategies in male and female patients with aphasia has more clinical importance. Though both research studies may yield statistically significant results, the clinical importance of the latter is far greater than the former. Research showing which confrontational naming strategies yield the highest success rates in male and female aphasic patients give clinicians valuable clinical procedures to be used in therapy.

No one would argue that pure research, and applied research not yielding important clinical information, contribute to the general body of knowledge in communication sciences and disorders and have inherent value. Research on muscle and nerve functions, respiratory pressure and airflow, tongue trajectories during phoneme productions, differences between males and females on clinical tasks, cultural variations in language usage, and velopharyngeal functioning during nasal speech, to name a few areas of investigation, can provide general information about human communication and its disorders. Current popular areas of pure research in speech and hearing sciences such as brain mapping research, studies localizing various parts of the brain to speech and hearing functions, can yield exciting information about how the brain and nervous system function during normal and abnormal communication. The human quest for knowledge about speech, voice, language, and hearing requires that pure, non-applied research be funded, competently conducted, and the results disseminated. However, as the discipline of communication sciences and disorders enters the 21st Century, this type of research should be of secondary importance to applied clinical research. This is especially true given recent changes in the scientific demographics in communication sciences and disorders.

Today, as in the past, there are limited research funding resources. There is a finite amount of dollars available to advance the knowledge base in communication sciences and disorders. Additionally, there is an increasingly smaller number of scientists in the discipline. During the past two decades, the percentage of scientists in communication sciences and disorders has declined dramatically. Doctoral programs in communication sciences and disorders have been eliminated, and the number of new doctoral graduates continues to decline. There are fewer scientists in the discipline, especially as a percentage of clinical providers. Also, during the past two decades, the number of clinicians and their scope of practice in speech-language pathology and audiology has increased dramatically.

There are more practitioners than ever before performing a wider range of services. This has created a situation where the scientific base of important applied clinical research has plummeted while the need for it has soared. Consequently, given this fundamental decline in the scientific base for communication sciences and disorders, pure research in communication sciences and disorders is often done at the expense of crucially needed, high quality applied research. If communication sciences and disorders, as a discipline, continues to aspire as science, it needs to redirect its research priority to the applied sciences and increase, not only the number but also the clinical importance, of its research base. The discipline is rapidly losing its applied scientific base and pure research, at the expense of applied research, is a luxury it not longer can afford.