Güç Analizi ve Örneklem Büyüklüğü Hesaplamasına Giriş
Synopsis
Bilimsel araştırmaların tasarım aşamasında gerçekleştirilen güç analizi ve örneklem büyüklüğü hesaplamaları, çalışmanın istatistiksel etkinliğini, etik uygunluğunu ve ekonomik verimliliğini belirleyen temel unsurlardır. Örneklem büyüklüğünün hatalı seçilmesi, gerçekteki önemli farkların saptanamamasına (Tip II hata) veya klinik olarak önemsiz farkların anlamlıymış gibi görünmesine yol açarak kaynak israfına ve etik sorunlara neden olabilir. Bu süreç; etki büyüklüğü, varyans, güven düzeyi ve hedeflenen istatistiksel güç gibi faktörlerden doğrudan etkilenmekte olup, doğru metodolojiyle belirlenen optimal örneklem sayısı araştırmanın bilimsel niteliğini ve güvenilirliğini garanti altına alır.
Power analysis and sample size calculations performed during the design phase of scientific research are fundamental elements that determine the statistical effectiveness, ethical compliance, and economic efficiency of a study. Incorrect selection of sample size can lead to the failure to detect significant differences (Type II error) or cause clinically insignificant differences to appear statistically significant, resulting in resource waste and ethical concerns. This process is directly influenced by factors such as effect size, variance, confidence level, and target statistical power, and an optimal sample size determined through correct methodology ensures the scientific quality and reliability of the research.
References
Cohen J. Statistical power analysis for the behavioral sciences , Lawrence Erlbaum Associates. Hillsdale, NJ, 20-26, 1988. ISBN 0-8058-0283-5.
Faber J, Fonseca LM. How sample size infuences research outcomes. Dental Press Journal of Orthodontics, 2014, 19(4), 27–29. 7 https://doi.org/10.1590/2176-9451.19.4.027-029.ebo.
Fugard AJB, Potts HWW. Supporting thinking on sample sizes for thematic analyses: A quantitative tool. International Journal of Social Research Methodology, 2015. 7 https://doi.org/10.1080/ 13645579.2015.1005453.
Sencer M, Sencer Y. Toplumsal araştırmalarda yöntembilim. Ankara: Türkiye ve Orta Doğu Amme İdaresi Enstitüsü Yayını, 1978.
Ioannidis, J. P. A. (2005). Why most published research findings are false. PLoS Medicine 2(8), e124. 7 https://doi.org/10.1371/journal.pmed.0020124.
SAS/STAT® 14.1 User’s Guide Introduction to Regression Procedures (15.01.2022 tarihinde https://support.sas.com/documentation/onlinedoc/stat/131/intropss.pdf adresinden ulaşılmıştır.)
Lachin M. Introduction to sample size determination and power analysis for clinical trials. Controlled Clinical Trials, 1981, 2(2), 93–113.
Jones S, Carley S, Harrison M. An introduction to power and sample size estimation. Emergency medicine journal: EMJ, 2003, 20(5), 453.
Driscoll P, Wardrope J. An introduction to statistics. J Accid Emerg Med, 2000;17:205.
Gore SM, Altman DG. How large a sample. In: Statistics in practice. London: BMJ Publishing, 2001:6–8.
Buderer NM. Statistical methodology: I. Incorporating the prevalence of disease into the sample size calculation for sensitivity and specificity. Academic Emergency Medicine 1996;3:895–900.
Sterne JA, Smith DG. (2001). Sifting the evidence—What’s wrong with signifcance tests. BMJ, 322, 226–231.
Araştırma Evreni, Örneklem Seçimi ve Ölçüm (16.01.2022 tarihinde https://www.bingol.edu.tr/media/210799/sayt-bolum12-Arastirma-Evreni-Orneklem-Secimi-ve-Olcum.pdf adresinden ulaşılmıştır.)
Guo Y, Logan HL, Glueck DH, et al. Selecting a sample size for studies with repeated measures. BMC Medical Research Methodology 2013; 13(1):1-8.
Suresh KP, Chandrashekara S. Sample size estimation and power analysis for clinical research studies. Journal of Human Reproductive Sciences 2012; 5(1):7.
Liu X. Statistical power and optimum sample allocation ratio for treatment and control having unequal costs per unit of randomization. Journal of Educational and Behavioral Statistics 2003; 28(3): 231-248.
Torgerson D. Designing randomised trials in health, education and the social sciences: an introduction. New York: Palgrave Macmillan; 2012.
Rusticus SA, Lovato CY. Impact of Sample Size and variability on the Power and Type I Error Rates of Equivalence Tests: A Simulation Study. Practical Assessment, Research & Evaluation 2014; 19(11).
Lehmann EL. Nonparametrics: Statistical Methods Based on Ranks. Springer, 2006
Kalaycıoğlu O, Akhanlı SE. Sağlık araştırmalarında güç analizinin önemi ve temel prensipleri: Tıbbi çalışmalar üzerinde uygulamalı örnekler. Turkish Journal of Public Health, 2020, 18(1), 103-112.
Wacholder S, Chanock S, Garcia-Closas M, et al. Assessing the probability that a positive report is false: An approach for molecular epidemiology studies. Journal of the National Cancer Institute, 2004, 96, 434–442.
