Abstract
Effect size is a statistical index that measures the magnitude of the effect generated by the variable of interest in a study, in a sense, reflecting the practical or clinical value of the study in addition to the statistical results. In recent years, it has become preferable to report the effect size expressing practical significance in addition to the statistical significance expressed by the p-value in hypothesis tests in scientific research, and even it has been required by some scientific journals. By reporting the effect size, it is possible to use it in statistical power analysis, to compare the results of the studies, and to determine the amount of the effect in the study. In this study, by mentioning the concept of effect size, some effect size indices calculated according to research designs are introduced with examples of the field of veterinary medicine.
Keywords
Clinical significance Effect size Hypothesis testing Power analysis Statistical significance
References
- 1. Thompson B. “Statistical”, “Practical”, and “Clinical”: How many kinds of significance do counselors need to consider?. Journal of Counseling&Development, 2002; 80: 64-71.
- 2. Pearson, K. On the criterion that a given system of deviations from the probable in the case of a correlated system of variables is such that it can be reasonably supposed to have arisen from random sampling. Philos Mag., 1900; 50: 157-175.
- 3. Student. The probable error of a mean. Biometrika, 1908; 6: 1–25.
- 4. Fisher RA, The correlation between relatives on the supposition of mendelian inheritance. Trans R.Soc Edinb., 1918, 53: 399–433.
- 5. Fisher, R.A. (1925). Statistical methods for research workers. (11th ed. rev.). Edinburgh: Oliver & Boyd.
- 6. Fisher, R. A. (1935). The design of experiments. Edinburgh: Oliver & Boyd.
- 7. Yıldırım HH, Yıldırım S (2011). On hypothesis testing, confidence interval, effects size, and noncentral probability distributions. Elementary Education Online, 2011; 10(3): 1112-1123.
- 8. Cohen J. The earth is round (p<0.05). American Psychologist, 1994; 49: 997-1003.
- 9. Rosnow RL, Rosenthal R. Statistical procedures and the justification of knowledge in psychological science. American Psychologist, 1989; 44: 1276-1284.
- 10. Vacha-Haase T, Thompson B. How to estimate and interpret various effect sizes. Journal of Counseling Psychology, 2004; 51(4): 473-481.
- 11. American Psychological Association (APA) Guide, Sixth Edition, 2010.
- 12. Nakagawa S, Cuthill IC. Effect size, confidence interval, and statistical significance: a practical guide for biologists. Biol. Rev., 2007; 82: 591-605.
- 13. Işık İ. Yokluk hipotezi anlamlılık testi ve etki büyüklüğü tartışmalarının psikoloji araştırmalarına yansımaları. Eleştirel Psikoloji Bülteni, 2014; 5: 55-80.
- 14. Cohen J (1988). Statistical power analysis for the behavioral sciences. (Second edit.). New Jersey: Lawrence Erlbaum Associates
- 15. Coe R. (2002). It’s the effect size, stupid: What effect size is and why it is important. Annual Conference of the British Educational Research Association, 12-14 September 2002, England.
- 16. Cooper H, Hedges LV, Valentine JC (1994). The handbook of research synthesis and meta-analysis. New York, Richard Sage Foundation. 221-253.
- 17. Hedges LV. Distribution Theory for Glass’s estimator of effect size and related estimators. Journal of Educational Statistics, 1981; 6(2): 107-128.
- 18. Süt N, Şenocak M. Relatif risk ölçütünün odds oranı, atfedilen risk ve tedaviye gerekli sayı ölçütleriyle karşılaştırılması. Trakya Üniv Tıp Fak Derg, 2007; 24(3): 213-221.
- 19. Kirk RE (1996). Practical significance: A concept whose time has come. Educational and Psychological Measurements, 1996; 56: 746-759.
Abstract
Etki büyüklüğü, bir çalışmada ilgilenilen değişkenin meydana getirdiği etkinin büyüklüğünü ölçen, bir anlamda çalışmanın istatistiksel sonuçlarına ek olarak, pratik veya klinik anlamdaki değerini de yansıtan istatistiksel bir indekstir. Son yıllarda bilimsel araştırmalarda hipotez testlerinde p değeri ile ifade edilen istatistiksel anlamlılığa ek olarak pratik anlamlılığı ifade eden etki büyüklüğünün de raporlanması tercih edilir hale gelmiş, hatta bazı bilimsel dergiler tarafından zorunlu kılınmıştır. Etki büyüklüğünün raporlanması ile istatistiksel güç analizinde yararlanılması, çalışmaların sonuçlarının karşılaştırılması ve çalışmada belirlenen etkinin miktarının belirlenmesi mümkün olmaktadır. Bu çalışmada etki büyüklüğü kavramından bahsedilerek, araştırma türlerine göre hesaplanan başlıca etki büyüklüğü indeksleri veteriner hekimliği alanından örnekler ile tanıtılmıştır.
References
- 1. Thompson B. “Statistical”, “Practical”, and “Clinical”: How many kinds of significance do counselors need to consider?. Journal of Counseling&Development, 2002; 80: 64-71.
- 2. Pearson, K. On the criterion that a given system of deviations from the probable in the case of a correlated system of variables is such that it can be reasonably supposed to have arisen from random sampling. Philos Mag., 1900; 50: 157-175.
- 3. Student. The probable error of a mean. Biometrika, 1908; 6: 1–25.
- 4. Fisher RA, The correlation between relatives on the supposition of mendelian inheritance. Trans R.Soc Edinb., 1918, 53: 399–433.
- 5. Fisher, R.A. (1925). Statistical methods for research workers. (11th ed. rev.). Edinburgh: Oliver & Boyd.
- 6. Fisher, R. A. (1935). The design of experiments. Edinburgh: Oliver & Boyd.
- 7. Yıldırım HH, Yıldırım S (2011). On hypothesis testing, confidence interval, effects size, and noncentral probability distributions. Elementary Education Online, 2011; 10(3): 1112-1123.
- 8. Cohen J. The earth is round (p<0.05). American Psychologist, 1994; 49: 997-1003.
- 9. Rosnow RL, Rosenthal R. Statistical procedures and the justification of knowledge in psychological science. American Psychologist, 1989; 44: 1276-1284.
- 10. Vacha-Haase T, Thompson B. How to estimate and interpret various effect sizes. Journal of Counseling Psychology, 2004; 51(4): 473-481.
- 11. American Psychological Association (APA) Guide, Sixth Edition, 2010.
- 12. Nakagawa S, Cuthill IC. Effect size, confidence interval, and statistical significance: a practical guide for biologists. Biol. Rev., 2007; 82: 591-605.
- 13. Işık İ. Yokluk hipotezi anlamlılık testi ve etki büyüklüğü tartışmalarının psikoloji araştırmalarına yansımaları. Eleştirel Psikoloji Bülteni, 2014; 5: 55-80.
- 14. Cohen J (1988). Statistical power analysis for the behavioral sciences. (Second edit.). New Jersey: Lawrence Erlbaum Associates
- 15. Coe R. (2002). It’s the effect size, stupid: What effect size is and why it is important. Annual Conference of the British Educational Research Association, 12-14 September 2002, England.
- 16. Cooper H, Hedges LV, Valentine JC (1994). The handbook of research synthesis and meta-analysis. New York, Richard Sage Foundation. 221-253.
- 17. Hedges LV. Distribution Theory for Glass’s estimator of effect size and related estimators. Journal of Educational Statistics, 1981; 6(2): 107-128.
- 18. Süt N, Şenocak M. Relatif risk ölçütünün odds oranı, atfedilen risk ve tedaviye gerekli sayı ölçütleriyle karşılaştırılması. Trakya Üniv Tıp Fak Derg, 2007; 24(3): 213-221.
- 19. Kirk RE (1996). Practical significance: A concept whose time has come. Educational and Psychological Measurements, 1996; 56: 746-759.
Details
| Primary Language | English |
|---|---|
| Subjects | Health Care Administration |
| Journal Section | Reviews |
| Authors | |
| Publication Date | April 30, 2021 |
| Submission Date | November 9, 2020 |
| Published in Issue | Year 2021 Volume: 6 Issue: 1 |
