Hello Alfonso and Juian, 

wound't then be that the effect size represents beta values?

I came across an old post from K Friston saying "I am using the term 'effect size' in reference to the
'size of the effect' (i.e. a measure of the modeled effect that
reflects the parameter estimate as opposed to the statistic that is
used for inference."
https://www.jiscmail.ac.uk/cgi-bin/wa.ex...


Can that be it?

Thanks, 

Athena