Stratification is an important design feature of many studies using complex sampling designs and it is often used in large-scale assessment (LSA) studies, such as the "Programme for International Student Assessment" (PISA), for two main reasons. First, stratification variables that achieve a high between and low within strata variance…

Background: Teachers' team innovativeness--the collective capacity of teaching teams to generate, adopt, and implement new ideas and practices--is increasingly recognized for its role in enhancing instructional methods and fostering school innovation. However, empirical research identifying its predictors remains limited, particularly within…