I should start by saying that I posted the same question that I will expose here on the psychological research forum. However, as I did not receive any answer, I wonder whether I misplaced my post. I apologize if this kind of repetition contravenes any of the rules of Talk Stats.

My problem is that I am trying to calculate the size of the difference between the means of two groups in a psychological test. However, I am not using my own data but those published in an article and authors do report test performance in Z scores. Therefore, I am wondering whether or not I can just apply the regular formula of Cohen's d to calculate the size of the observed difference.

Thanks in advance for any possible help