There are three key phases in an Assessment Programme: a conceptual framework, a methodological framework, and a reporting framework.
The design of an assessment/survey is defined by its purpose and by defining what to measure and how to measure it. The decisions made in this phase affect the possibilities of what can be done with the data collected.
There are many operational issues that affect both quality and comparability. Since SDG 4 data cover many countries and include many different initiatives, it is essential to define some minimum good practices for assessment programmes to follow while respecting national authority and autonomy.
Each assessment uses different standard-setting approaches to build levels of performance so that the scores can be classified in different categories. For education systems participating in the same cross-national learning assessments, results are comparable, but results are not comparable across different cross-national learning assessments or between national assessments.