title: Sample size: how many participants do I need in my research?
abstract: The importance of estimating sample sizes is rarely understood by researchers, when planning a study. This paper aims to highlight the centrality of sample size estimations in health research. Examples that help in understanding the basic concepts involved in their calculation are presented. The scenarios covered are based more on the epidemiological reasoning and less on mathematical formulae. Proper calculation of the number of participants in a study diminishes the likelihood of errors, which are often associated with adverse consequences in terms of economic, ethical and health aspects.
authors: Latin American Cooperative Oncology Group, Porto Alegre, RS, Brazil.
authors: Jeovany
authors: J
authors: Martínez-Mesa
authors: Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
authors: David Alejandro
authors: DA
authors: González-Chica
authors: Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
authors: João Luiz
authors: JL
authors: Bastos
authors: Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil.
authors: Renan Rangel
authors: RR
authors: Bonamigo
authors: Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil.
authors: Rodrigo Pereira
authors: RP
authors: Duquia
mesh_terms: D035843:Biomedical Research / Q000592:standards*; D003880:Dermatology; D006801:Humans; D012016:Reference Values; D012307:Risk Factors; D018401:Sample Size