most papers on detrital zircons give numbers for discordance but I could find only one paper saying how that is done:
discordance = (1-(206Pb/238U age /207Pb/206Pb age)*100 - is that right? shouldn't it be
1/(1-(206Pb/238U age / 207Pb/235U age)*100
which in my view better describes the "distance" to the concordia.