1. Capili, Bernadette PhD, NP-C
  2. Anastasi, Joyce K. PhD, DrNP, FAAN


Editor's note: This is the 14th article in a series on clinical research by nurses. The series is designed to be used as a resource for nurses to understand the concepts and principles essential to research. Each column will present the concepts that underpin evidence-based practice-from research design to data interpretation. To see all the articles in the series, go to