the three primary channels of influence by which national standards could affect teaching and learning and notes ways these can interact with one another.

• allow sufficient time for the education components under investigation to have been affected by nationally developed standards? The Framework demonstrates the complexity of the system through which messages about standards-based practice must move, thus the effects may become visible only after an extended period of time.

Again, these are not all of the important questions to be asked about the findings and conclusions of research related to nationally developed standards in mathematics, science, or technology education. Other important questions include congruence of the research design with the research questions, execution of the design, adequacy of the database, and quality of data-analysis approaches. Still, the Framework establishes a conceptual map that provides relevance and meaning for answers to such additional questions.

The Framework can help pinpoint areas of potential influences operating within the education system that may or may not have been considered by particular studies. This third main application of the Framework has two parts:

• Assembling knowledge. The Framework offers a basis for assembling knowledge gained from existing studies. Using Framework components as organizers, research syntheses and reviews can summarize what has been learned about the extent to which the education system has changed in response to nationally developed standards, particularly in terms of classroom practice and student learning.