**Module Description**
This module addresses what effect sizes are, how to calculate them, and how to interpret them.
**Learning Objectives**
1. Identify the appropriate effect size to use in different situations.
2. Calculate a variety of effect sizes: Difference, Correlaction, and Category.
3. Interpret effect sizes.
4. Calculate confidence intervals for effect sizes
5. Articulate controversies related to effect sizes
**Readings**
[We cannot afford to study effect size in the lab][1]
[Gelman, A., & Carlin, J. (2014). Beyond power calculations: Assessing Type S (sign) and Type M (magnitude) errors. Perspectives on Psychological Science, 9(6), 641-651.][2]
[Greenwald, A. G., Banaji, M. R., & Nosek, B. A. (2015). Statistically small effects of the Implicit Association Test can have societally large effects. Journal of Personality and Social Psychology, 108(4), 553–561. http://doi.org/10.1037/pspa0000016][3]
[Lakens, D. (2013). Calculating and reporting effect sizes to facilitate cumulative science: A practical primer for t-tests and ANOVAs. Frontiers in psychology, 4.][4]
[Lo, A., Chernoff, H., Zheng, T., & Lo, S.-H. (2015). Why significant variables aren’t automatically good predictors. Proceedings of the National Academy of Sciences, 112(45), 13892–13897.http://doi.org/10.1073/pnas.1518285112][5]
[Prentice, D. A., & Miller, D. T. (1992). When small effects are impressive. Psychological Bulletin, 112, 160-164][6]
[Richard, F. D., Bond, C. F., & Stokes-zoota, J. J. (2003). One hundred years of social psychology quantitatively described. Review of General Psychology, 7(4), 331-363.][7]
[Cumming, G. (2014). The new statistics: Why and how. Psychological science, 25(1), 7-29.][8]
[Fritz, C. O., Morris, P. E., & Richler, J. J. (2012). Effect size estimates: Current use, calculations, and interpretation. Journal of Experimental Psychology: General, 141, 2-18. doi:10.1037/a0024338][9]
[Daniel Laken's blog posts about effect size][10]
[Lakens, D. (2013). Calculating and reporting effect sizes to facilitate cumulative science: A practical primer for t-tests and ANOVAs. Frontiers in Psychology, 4:863. doi:10.3389/fpsyg.2013.00863][11] *[Supplements][12]*
http://jakewestfall.org/blog/index.php/2016/03/25/five-different-cohens-d-statistics-for-within-subject-designs/
Pek, J., & Flora, D. B. (2017). Reporting effect sizes in original psychological research: A discussion and tutorial. Psychological Methods.
**Demonstration**
[The New Statistics: Estimation and Research Integrity][13]
[The New Statistics:Why and How][14]
[Interpreting Cohen's d effect size an interactive visualization][15]
[Interpreting Correlations an interactive visualization][16]
[Week 4 of Daniel Lakens Improving Your Statistical Inference course on Coursera][17]
Effect size calculator: http://www.cem.org/effect-size-calculator
Dance of the p's: http://www.youtube.com/watch?v=ez4DgdurRPg
**Assignments**
[13[]: https://www.coursera.org/learn/statistical-inferences/home/info
[1]: http://datacolada.org/20
[2]: http://www.stat.columbia.edu/~gelman/research/published/retropower_final.pdf
[3]: https://faculty.washington.edu/agg/pdf/Greenwald,Banaji&Nosek.JPSP.2015.pdf
[4]: http://journal.frontiersin.org/article/10.3389/fpsyg.2013.00863/full
[5]: http://asiapolmeth.princeton.edu/sites/default/files/polmeth/files/pnas-2015-lo-13892-final_withsi.pdf
[6]: http://www.psychologicalscience.org/members/new-statistics#p3
[7]: http://jenni.uchicago.edu/Spencer_Conference/Representative%20Papers/Richard%20et%20al,%202003.pdf
[8]: http://www.psychologicalscience.org/members/new-statistics#p4
[9]: https://pdfs.semanticscholar.org/63ea/7f6c0ded688aa717e1a6d35496569e1f8cb5.pdf
[10]: http://daniellakens.blogspot.com/search?q=effect%20size
[11]: http://journal.frontiersin.org/article/10.3389/fpsyg.2013.00863/full
[12]: https://osf.io/ixGcd/
[13]: http://www.psychologicalscience.org/members/new-statistics#p3
[14]: http://www.psychologicalscience.org/members/new-statistics#p4
[15]: http://rpsychologist.com/d3/cohend/
[16]: http://rpsychologist.com/d3/correlation/
[17]: http://rpsychologist.com/d3/correlation/
