I focus here on one after-assignment condition that may notably affect the logic of the RCT and the CGT designs, particularly the central assumption that, all other things being equal, observed differences if any between experimental (E, treatment) and nonexperimental (C, control, comparison) groups are attributable to the treatment. My concern might be characterized as augmentation of the control and experimental groups with relevant non-program services in non-random, potentially biasing, ways. Somewhat more attention will be given to the experiences of the C group because of this group's particular significance for the logic of the RCT. (author abstract)