R help - Aug 2008 - selection bias adjustment via propensity score

Hi all,

i am wondering if there?s any other method to adjust for selection  
related bias of estimates except propensity scoring and heckit / mills  
ratio approach? i also read documentation of Match and twang package  
so far, so i don?t speak of any ATE / ATT related methods,  
respectively any methods that match or stratify... Is there something  
else ?

thx in advance