Power and effect size: research considerations for the clinical nurse specialist.

Frequently, a goal for a Clinical Nurse Specialist (CNS) is to determine whether research results are clinically meaningful and appropriate for adoption into practice. Often, the evaluation of research involves an examination of the efficacy and cost-effectiveness of the intervention under study. Attention to two concepts from research methodology--power and effect size--can help the CNS evaluate research findings and design studies to produce clinically meaningful results.