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Statistically nonsignificant results with small effect sizes (f square) in large samples

Posted: Tue Jul 03, 2018 9:47 am
by FJAM
Hi, good morning

Using Cohen's f square, I am getting a small effect size (0.024) for a result that is statistically non-significant using a large sample (12000 individuals). Does this make sense?

I know that as the sample size grows, it is quite possible to find statistically significant results with no effects (f2<0.02), but I'm not sure if small effects (f2>0.02) in non-significant relationships are correct.

The confidence interval for this f square stimation is as follows (SmartPLS V 3.2.3):
Original Sample (O) - Sample Mean (M) - 2.5% - 97.5%
0.024 - 0.045 - 0.000 - 0.180

Thank you very much,
Francisco

Re: Statistically nonsignificant results with small effect sizes (f square) in large samples

Posted: Wed Jul 04, 2018 8:10 am
by jmbecker
Sure it is possible. You might sample an exceptionally large effect where there is indeed no effect. Even a very large sample size might not prevent you from doing so. In addition, the f² effect sizes are always positive, but your confidence interval also indicates that you are touching the zero, hence the effect size might also not be significantly different from zero.

Re: Statistically nonsignificant results with small effect sizes (f square) in large samples

Posted: Wed Jul 04, 2018 9:20 am
by FJAM
Thank you very much for your answer!
F.Arenas
jmbecker wrote: Wed Jul 04, 2018 8:10 am Sure it is possible. You might sample an exceptionally large effect where there is indeed no effect. Even a very large sample size might not prevent you from doing so. In addition, the f² effect sizes are always positive, but your confidence interval also indicates that you are touching the zero, hence the effect size might also not be significantly different from zero.