title: Sample size: how many is enough?
abstract: Sample size is an element of research design that significantly affects the validity and clinical relevance of the findings identified in research studies. Factors that influence sample size include the effect size, or difference expected between groups or time points, the homogeneity of the study participants, the risk of error that investigators consider acceptable and the rate of participant attrition expected during the study. Appropriate planning in regard to each of these elements optimises the likelihood of finding an important result that is both clinically and statistically meaningful.
authors: Nursing Practice Development Unit, Princess Alexandra Hospital & Research Centre for Clinical and Community Practice Innovation, Griffith University, Brisbane, QLD, Australia. Liz_Burmeister@health.qld.gov.au
authors: Elizabeth
authors: E
authors: Burmeister
authors: Leanne M
authors: LM
authors: Aitken
mesh_terms: D006801:Humans; D015233:Models, Statistical; D015399:Nursing Research; D012107:Research Design; D018401:Sample Size