FAQs about Effect Size

• What is an effect size?
• Can you give me some examples of an effect size?
• Why does my research methods textbook have no entry for “effect size”?
• How to report an effect size
• Cohen’s effect sizes
• 3 reasons for reporting effect sizes
• Why are journal editors increasingly asking authors to report effect sizes?
• Which editors encourage the reporting of effect sizes?
• Why can’t I just judge my result by looking at the p value?
• Why can’t I just report the R²?
• What are the two families of effect size?
• What’s a good effect size index for comparing the means of two groups?
• Where can I find a good effect size calculator?
• How to interpret an effect size
• Can you recommend a plain English introduction to effect sizes?

FAQs about Statistical Power

• What is statistical power?
• How to calculate statistical power?
• How to increase statistical power?
• What is an ideal level of statistical power?
• What do alpha and beta refer to in statistics?
• What’s the difference between Type I and II errors?
• How big a sample size do I need to test my hypotheses?
• How do I know if my study has enough statistical power?
• What’s wrong with post hoc power analyses?
• Can you recommend a good power calculator?
• Can you recommend a plain English introduction to power analysis?

FAQs about Interpreting Research Results

• What is the difference between statistical and substantive significance?
• How do researchers confuse statistical with substantive significance?
• Can a result be statistically nonsignificant but important?
• Why should I interpret the substantive significance of my results?
• Which journal editors insist researchers interpret the substantive significance of their results?
• What does a statistical significance test actually tell us?
• What does a p value represent?
• Why is it a dumb idea to interpret results by looking at p values?
• Why do you say a p value is a confounded index?
• What are some conventions for interpreting different effect sizes?
• When are small effects important?
• What is the “curse of multiplicity”?

FAQs about Meta-Analysis

• What are two approaches to reviewing past research?
• What is meta-analysis?
• What are three good reasons for doing a meta-analysis?
• Meta-analysis vs literature review
• Why are you so convinced I can learn meta-analysis?
• How to do meta analysis