125
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      How sample size influences research outcomes

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Sample size calculation is part of the early stages of conducting an epidemiological, clinical or lab study. In preparing a scientific paper, there are ethical and methodological indications for its use. Two investigations conducted with the same methodology and achieving equivalent results, but different only in terms of sample size, may point the researcher in different directions when it comes to making clinical decisions. Therefore, ideally, samples should not be small and, contrary to what one might think, should not be excessive. The aim of this paper is to discuss in clinical language the main implications of the sample size when interpreting a study.

          Translated abstract

          O cálculo amostral faz parte dos estágios iniciais de realização de um estudo epidemiológico, clínico ou laboratorial. Há indicações éticas e metodológicas para o seu emprego na elaboração de um trabalho científico. Duas pesquisas, realizadas com a mesma metodologia obtendo resultados equivalentes, e que diferem apenas no tamanho da amostra, podem apontar para diferentes direções no processo de tomada de decisão clínica. Portanto, as amostras estudadas idealmente não devem ser pequenas e, ao contrário do que pode-se pensar, não devem ser excessivas. O objetivo desse artigo é discutir, numa linguagem clínica, as principais implicações do tamanho das amostras na interpretação de um estudo.

          Related collections

          Most cited references4

          • Record: found
          • Abstract: not found
          • Article: not found

          Practical statistics for medical research. Douglas G. Altman, Chapman and Hall, London, 1991. No. of pages: 611. Price: £32.00

            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Sample size estimation: an overview with applications to orthodontic clinical trial designs.

            Proper sample size estimation is an important part of clinical trial methodology and closely related to the precision and power of the trial's results. Trials with sufficient sample sizes are scientifically and ethically justified and more credible compared with trials with insufficient sizes. Planning clinical trials with inadequate sample sizes might be considered as a waste of time and resources, as well as unethical, since patients might be enrolled in a study in which the expected results will not be trusted and are unlikely to have an impact on clinical practice. Because of the low emphasis of sample size calculation in clinical trials in orthodontics, it is the objective of this article to introduce the orthodontic clinician to the importance and the general principles of sample size calculations for randomized controlled trials to serve as guidance for study designs and as a tool for quality assessment when reviewing published clinical trials in our specialty. Examples of calculations are shown for 2-arm parallel trials applicable to orthodontics. The working examples are analyzed, and the implications of design or inherent complexities in each category are discussed. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.
              Bookmark
              • Record: found
              • Abstract: not found
              • Article: not found

              Sample size estimation: an overview with applications to orthodontic clinical trial designs

                Bookmark

                Author and article information

                Journal
                Dental Press J Orthod
                Dental Press J Orthod
                Dental Press Journal of Orthodontics
                Dental Press International
                2176-9451
                2177-6709
                Jul-Aug 2014
                Jul-Aug 2014
                : 19
                : 4
                : 27-29
                Affiliations
                [1 ] Adjunct professor, Department of Orthodontics, University of Brasília.
                [2 ] Invited Professor, Department of Orthodontics, University of Brasília.
                Author notes
                Contact address: Jorge Faber, Brasília Shopping, SCN Q. 5 - bloco A - sala 408 Brasília/DF - Brazil CEP: 70.715-900. E-mail: faber.jorge@ 123456gmail.com
                Article
                10.1590/2176-9451.19.4.027-029.ebo
                4296634
                25279518
                64bfc4ce-fe66-4cdc-a89c-0792118c9c69
                © 2014 Dental Press Journal of Orthodontics

                This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

                History
                : 20 May 2014
                : 02 June 2014
                Categories
                Evidence-based Orthodontics

                sample calculation,sample size,clinical trial,methodology,scientific evidence

                Comments

                Comment on this article