Palmer R F, Graham J W, White E L, Hansen W B
Department of Biobehavioral Health, College of Health and Human Development, Penn State University, University Park 16802, USA.
Prev Med. 1998 May-Jun;27(3):328-36. doi: 10.1006/pmed.1998.0311.
School-based drug prevention programs have been criticized on methodologic grounds because the unit of analysis is often not the unit of randomization, thus increasing the likelihood of Type I errors. Application of multilevel analytic strategies appropriately corrects this biasing tendency. This study demonstrates the practical use of such analysis.
Data from 2,370 seventh-grade students participating in a substance use prevention trial were analyzed using a multilevel strategy. We examined the effectiveness of a social pressure resistance training and a normative education (NORM) intervention against an information-only control group.
The NORM condition revealed 1-year program effects for cigarette and marijuana use with individuals as the unit of analysis and only marginal effects with classroom as the unit of analysis. No program effects were found using school as the analysis unit. A multilevel strategy revealed program effects for cigarettes and marijuana with both class and school as grouping levels. The effect for alcohol use was significant at the 2-year follow-up.
Interventions establishing conservative drug use norms in classrooms may be an effective strategy in reducing substance use onset among adolescents. Utilization of appropriate analytic strategies is important in the analysis and interpretation of data containing nested structures.
基于学校的药物预防项目在方法学上受到批评，因为分析单位往往不是随机化单位，从而增加了I类错误的可能性。应用多层次分析策略可适当纠正这种偏差趋势。本研究展示了此类分析的实际应用。
采用多层次策略对参与物质使用预防试验的2370名七年级学生的数据进行分析。我们对照仅提供信息的对照组，检验了社会压力抵抗训练和规范教育（NORM）干预的效果。
以个体为分析单位时，NORM条件显示出对香烟和大麻使用的1年项目效果；以课堂为分析单位时，仅显示出边际效果。以学校为分析单位时未发现项目效果。多层次策略显示，以班级和学校作为分组水平时，对香烟和大麻有项目效果。在2年随访时，对酒精使用的效果显著。
在课堂上建立保守的药物使用规范的干预措施可能是减少青少年物质使用开始的有效策略。在分析和解释包含嵌套结构的数据时，使用适当的分析策略很重要。
