Although many non-experimental studies have suggested that high percentages of families remain intact after intensive family preservation services, the results of randomized experiments provide more convincing tests of the extent to which "placement prevention rates" can be attributed to the effects of these programs. The findings of the controlled studies we reviewed are mixed: Seven of the eleven randomized experiments (Hennepin County Community Services Department 1981; Nebraska Department of Public Welfare 1981; Willems and DeRubeis 1981; Szykula and Fleischman 1985; Yuan et al. 1990; Meezan and McCroskey 1993; Schuerman, Rzepnicki, and Littell 1994) and one overflow group study (Mitchell, Tovar, and Knitzer 1989) found that the programs did not produce significant overall reductions in placement. Four randomized experiments (Jones, Neuman, and Shyne 1976; Halper and Jones 1981; Lyle and Nelson 1983; Feldman 1991) and three overflow comparison studies (Wood, Barton, and Schroeder 1988; Schwartz, AuClaire, and Harris 1991; Pecora, Fraser, and Haapala 1992) found significant reductions in placement in favor of the experimental groups.
In studies that found significant reductions in placement, differences between groups were relatively small. For example, in New Jersey, the difference between groups in the proportion of cases in placement at one year after treatment ended was 14 percent (Feldman 1991). Although larger differences were found in the overflow studies, questions about the comparability of groups in these studies remain and sample sizes were generally small. Small sample sizes are also a concern in the earlier experimental projects.
The fact that placement occurred within a short period of time after group assignment in less than half of the control or comparison cases in most studies suggests that these programs were generally not delivered to families with children at risk of placement. (The placement rate in a control group is an estimate of the risk of placement for both groups in the absence of experimental services.) When the risk of placement among family preservation clients is low, it is unlikely that a program will demonstrate significant reductions in placement. It is not meaningful to talk about preventing an event if the event wouldn't have happened anyway.
Finally, available evidence sheds little light on whether family preservation programs have differential effects on placement for different kinds of families or on the relative effectiveness of different approaches to placement prevention. Evidence of the effects of family preservation programs for specific subgroups of clients is scant and the results of available studies are somewhat contradictory. Although it is correlational in nature, the best available evidence suggests that features of services that are often considered among the hallmarks of family preservation programs--brevity and intensity of services and the provision of an array of concrete and specialized services--may not be critical.