Programs that improve teaching effectiveness represent a core strategy to improve student educational outcomes and close student achievement gaps. This article compiles empirical values of intraclass correlations for designing effective and efficient experimental studies evaluating the effects of these programs. The Early Childhood Longitudinal…

Since its inception, the National Center for Education Statistics (NCES) has been committed to the practice of documenting its statistical methods for its customers and of seeking to avoid misinterpretation of its published data. The reason for this policy is to assure customers that proper statistical standards and techniques have been observed,…

The Early Childhood Longitudinal Study (ECLS) is a new study that will focus on children's early school experiences beginning in kindergarten. Approximately 23,000 children will be selected as they enter kindergarten and followed through fifth grade. Base-year data will be collected in the fall of 1998, but there will a field test in the 1996-97…

Recent investigations of the extent to which students with disabilities are allowed to participate in major national data collections used in measurement-driven education reform suggest that 40 to 50 percent of students with disabilities are typically excluded from major assessments, although they are included to a greater degree in assessments…