... eigentlich fast immer:

bei wired lese ich von der Praxiserprobung von "the effect of pesticides" - die Probanden sollten Kinder sein: "Over the study's two years, EPA had planned to give $970 plus a camcorder and children's clothes to each of the families of 60 children in Duval County, Florida, in what critics of the study noted was a low-income minority neighborhood. ..."

Die Studie war dann doch kontrovers und wurde gestoppt.