Detecting and Describing Preventive Intervention Effects
Detecting and Describing Preventive Intervention EffectsDetecting and Describing Preventive Intervention Effects in a Universal School-Based Randomized Trial Targeting Delinquent and Violent BehaviorMike Stoolmiller
Oregon Social Learning Center
Eugene, Oregon
J. Mark Eddy
Oregon Social Learning Center
Eugene, Oregon
John B. Reid
Oregon Social Learning Center
Eugene, Oregon
INTRODUCTION
I chose to summarize this article regarding the study of measurement of child aggression in empirical studies, because of the difficulty of conducting such studies. Here I summarize the article I studied, along with comments and my opinions on the findings.
Summary
This study examined theoretical, methodological, and statistical problems involved in evaluating the outcome of aggression on the playground for a universal preventive intervention for conduct disorder. Moderately aggressive children were hypothesized most likely to benefit. Aggression was measured on the playground using observers blind to the group status of the children. Behavior was microcoded in real time to minimize potential expectancy biases. The effectiveness of the intervention was strongly related to initial levels of aggressiveness. The most aggressive children improved the most.
First, participants are clustered within naturally occurring units (e.g., classroom, grade level, or school), and such nonindependence may significantly bias statistical tests of intervention outcome. For example, the aggressive behaviors of children might be observed on the playground for three 10-min observations conducted over a 3-week period at preintervention and three 10-min sessions 6 months later postintervention. The second component is due to true time-specific individual differences across children. Clearly, any true time-specific individual differences in behavior must be the result of time-specific, contextual determinants of aggressive behavior in the external social environment, the internal biological environment, or some combination or interaction of the two. Further, the true time-stable individual differences must also be due to time-stable internal or external determinants. I believe this opposes a risk for the study, if the children¡¦s If behavior is highly variable from one occasion to the next, or if differences in behavior rates are small, then reliability may be inadequate even if coders are perfectly accurate. If the experimenter fixes the observational period at the same constant value for all participants, the censoring is known as Type I censoring (Lawless, 1982). The waiting time is the reciprocal of the rate. In this study participants in both the control and intervention conditions were assessed during the fall (preintervention) and spring (postintervention) academic quarters. The intervention program was conducted during the winter quarter of the same school year and lasted 10 weeks.
Participants
The 12 schools participating in the study had an average enrollment detainment rate of 13% , an average yearly student turnover rate of 43% , and an average free-lunch rate of 47% of students. The final sample comprised 671 students (51% female), with 382 attending the intervention schools and 289 attending the control schools. Participants in the control and intervention groups shared similar background characteristics. Repeated live observations were conducted on the playground by professional observers blind to the intervention status of the school.
Analyses
In the SEM literature, this type of...
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