Redressing the power and effect of significance. A new approach to an old problem: teaching statistics to nursing students.

Many barriers to learning are present when teaching research methods. Developing, within students of nursing, the skills of reading and interpreting research reports is vital if the profession is to contribute to the general aim of achieving a sound basis for all health care interventions. This paper overviews the current move toward evidence based practice, the challenges that are present when teaching research to nursing students and offers an approach to teaching quantitative research that will help students of nursing to understand the key concepts that form the basis of inferential statistics. In this work we argue that the traditional emphasis on probability and statistical significance needs to be redressed and that effect size and power should form the basis of teaching students the concepts involved in inferential statistics. We argue that introducing students to the key concepts in statistical decision making in a particular order, effect size then power and lastly statistical significance, will lead to a better understanding of Type I and Type II errors. After all, the purpose of hypothesis testing is to detect a treatment or intervention effect. Power is dependent upon the size of the treatment effect, thus it must be introduced after effect size. Students, we argue, must be able to understand the concept of effect size. We consider this to be a foundational concept that will help to develop a firmer grasp of the decision making processes involved in hypothesis testing. Such an approach will form a more logical approach to teaching this subject and will allow for the use of real world examples to form the basis of learning.