R help - May 2010 - Discriminative power (Trennschärfe) calculations with R

Hi,

currently, i am a bit lost. i want to calculate the discriminative
power of items in my questionnaire. i have found the psych package
which should contain that sort of thing, but i cant find it in there.
by what name does it go? it probably does not help that i have got
onlygerman books on the subject, so i am not good with the names of
the methods...

thanks,

markus