udice and stereotypes more openly and thus encourage "prolonged engagement and...promote learning" (Tynes, 2007, p. 1318). This finding suggests that rather than a group intervention where youth are physically grouped in a room, an online format might facilitate the desired sharing and discussion without the threat of violence. However, this does not guarantee the absence of iatrogenic effects, as youth can collaborate online and then gather together offline unless their identities are kept hidden from one another. Moreover, the collaboration process itself can serve as an education in crime that promotes further aggression and delinquency on the part of individual participants even if they never aggregate. Thus, the iatrogenic effect might still apply, even in an anonymous format.
The iatrogenic effect is of even greater concern in groups where there is a disparity of delinquent behavior among the youth in an intervention group. Poulin, Dishion, and Burraston (2001, p. 214) found that in a preventive intervention trial involving high-
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