This study examined how ethnic composition and linguistic acculturation within schools affected the efficacy of a youth substance use prevention model program. Data came from a randomized trial of the keepin' it REAL program, using a predominantly Mexican American sample of middle school students in Phoenix, Arizona. Schools were randomly assigned to a control group or one of three culturally tailored intervention versions. The authors hypothesized that school ethnic and linguistic acculturation composition (percentage Latino, percentage non-English-speaking at home) and individual level of linguistic acculturation would jointly moderate the efficacy of the prevention program, as indicated by students' alcohol, marijuana, and cigarette use. With multilevel linear modeling and multiple imputation techniques used to manage clustered data and attrition, results show that desired program effects varied by linguistic acculturation level of the school, program version, and individual acculturation level. The Latino intervention version was more efficacious in schools with larger percentages of non-English-speaking families, but only among less linguistically acculturated Latino students. There were no significant school-level program effects connected to the percentage of Latino students at school or the other versions of the program, nor were there any such effects among more linguistically acculturated students.
KEY WORDS: acculturation; Hispanic/Latino; prevention; school composition; substance use
Drawing on prior work suggesting that some b predominately Latino schools may create uniquely protective environments for Latino students, at least in terms of their academic outcomes (Goldsmith, 2003; Morrison Institute for Public Policy/Center for the Future of Arizona, 2006), the present study tested whether the same might be true for substance use. It examined whether Latino predominance and the mix of more and less acculturated students in schools enhanced drug prevention program outcomes among Latino students. In addition, it explored whether the effects of school composition on program efficacy differed according to individual students' acculturation level.
NEED FOR CONTEXTUAL EFFICACY RESEARCH
Whether an intervention focuses on individual or contextual (for example, peer, family, community) factors, it is implemented in a specific context, the characteristics of which may influence its success. Many interventions have been shown to be efficacious in randomized controlled trials, but these results are tied to the contexts in which the trials were conducted. They do not guarantee success in alternate contexts, nor do they reveal whether the programs could have been more successful in alternate contexts. Effectiveness and replication studies aim to test program effects in alternate settings, but they leave open the possibility of program failure as a result of implementation in a context that undermines effectiveness, such as when there is a poor match between an intervention's design and content and the social and cultural context in which it is implemented. An alternative approach to contextual efficacy is to explicitly examine contextual factors that may enhance or undermine program efficacy for a given intervention. With advance knowledge of the contexts to which interventions are best suited, organizations can select interventions that are appropriate for the target context and not merely for the individuals at risk in that context.
Recent research has shed light on the distinction between individual and contextual levels when it comes to program efficacy. One study examined the efficacy of a universal substance use prevention program for Latino youths at different levels of risk for substance use, showing that the program achieved larger desired program outcomes for high-risk youths; this effect was explained in large part by treatment floor effects among the low-risk youths (Marsiglia, Kulis, Wagstaff, Elek, & Dran, 2005). A subsequent study including neighborhood-level predictors found that, for the high-risk youths, program efficacy was not moderated by neighborhood context, as defined by immigrant composition (Yabiku et al., 2007). The high-risk youths had similar program outcomes, regardless of the immigrant composition of the neighborhood. In contrast, the low-risk youths reported better program outcomes when they lived in neighborhoods with higher concentrations of immigrants. If program selection were based solely on the individual level of risk in the community, communities with low levels of individual risk might overlook this program, viewing it as appropriate only for communities with a high level of individual risk. However, as the study showed, the program is efficacious for low-risk youths who live in immigrant communities. And when it comes to prevention among youths, maintaining the protections that make youths "low risk" is valuable, because it is much harder to change than it is to maintain the status quo.
THE KEEPIN' IT REAL INTERVENTION
To address the need for contextual efficacy research, the present study examined the influence of school context on the efficacy of the keepin' it REAL youth substance use prevention program, keepin' it REAL is a school-based program, shown in a randomized trial to be efficacious in preventing substance use, strengthening antidrug norms and attitudes, and increasing the use of drug-resistance strategies (Hecht et al., 2003; Kulis et al., 2005; Marsiglia & Hecht, 2005). It is recognized by the Substance Abuse and Mental Health Services Administration (SAMHSA) (2003) as a model program. The intervention's name comes from an acronym of the four drug refusal skills that are stressed in the curriculum: refuse, explain, avoid, and leave. The published curriculum (Marsiglia & Hecht, 2005) was created using a participatory action research approach promoting input and dialogue from the community as well as from youths themselves (Gosin, Dustman, Drapeau, & Harthun, 2003).
A strength of the curriculum is that it was designed, from the start, to be culturally sensitive, making use of long-standing ethnic values that could aid youths in their attempts to avoid substance use (Castro, Proescholdbell, Abeita, & Rodriguez, 1999). Three versions of the program exist--Latino, black/white, and multicultural--each with a unique cultural emphasis. For example, in designing the Latino-based curriculum, program planners incorporated aspects of traditional Mexican culture (Gosin, Marsiglia, & Hecht, 2003). All versions include a 10-lesson, in-school, classroom-based curriculum designed to promote drug resistance and fife skills (Botvin, Griffin, Diaz, & Ifill-Williams, 2001). Overall, the curriculum's goals are to promote norms and attitudes that discourage substance use, improve students' decision-making skills, and increase their awareness of and ability to assess risks. For full details on the design of the program (including qualitative phases of development), its theoretical underpinnings, and the specific features of the local ethnic populations that influenced program content, see Holleran, Dustman, Reeves, and Marsiglia (2002) and Gosin, Marsiglia, and Hecht (2003).
Because keepin' it REAL is school based, attention to the school context in which it is implemented is warranted. Furthermore, the cultural grounding of the intervention calls for a focus on cultural characteristics of the context--hence this study's examination of school composition, defined in terms of proportion of Latino students and proportion of less linguistically acculturated students. Because there is little theory to guide thinking specifically about the effect of contexts on interventions, we must draw on theoretical and empirical work about the relationship between contexts and individual outcomes.
SCHOOL CONTEXT AND THE EFFICACY OF A CULTURALLY GROUNDED INTERVENTION
Role of the Normative Environment
Eco-developmental theory (Szapocznik & Coatsworth, 1999) posits that understanding of adolescent outcomes requires consideration of the social systems or contexts in which development occurs, and it focuses on the ways in which systems influence one another and the ways in which these sequences affect development. According to the theory, a school context characterized by high rates of use and pervasive prodrug norms and attitudes might contribute to substance use at the individual level.
Findings from studies of adolescent substance use are consistent with eco-developmental theory. Ennett, Flewelling, Lindrooth, and Norton (1997) found, for example, that schools that were more prodrug use at the aggregate (or school mean) level had higher levels of lifetime and current cigarette use and lifetime alcohol use. Kumar, O'Malley, Johnston, Schulenberg, and Bachman (2002) found that school-level disapproval of daily cigarette use, heavy drinking, and marijuana use was associated with lower probabilities of students' substance use, even among students who themselves approved of daily cigarette use. Kumar and colleagues argued that through a social learning process (Bandura, 1986), students within schools develop similar habits through the diffusion--or contagion--of prevailing norms (Ennett et al., 1997). Johnson and Hoffmann (2000) found that Latino students' and African American students' cigarette use decreased as their school's ethnic minority composition increased, and both groups reported less cigarette use than white students.
Drawing on the large literature associating adherence to Latino cultural norms and practices with less drug use (de la Rosa, 2002; Warner et al., 2006) and on Stanton-Salazar's (2004) work showing that youths from marginal groups in society can acquire social capital by connecting in school with like peers, Kulis, Marsiglia, Nieri, Sicotte, and Hohmann-Marriott (2004) examined whether Latino ethnic composition affected individual drug use norms or...