The document discusses the move in the UK education system away from using levels to assess student performance and toward focusing on key constructs. It outlines principles that assessment should meet, such as being reliable and valid. Problems with the previous level-based system are described, such as it encouraging pace over depth of learning. The concept of assessing students based on their understanding of core constructs or ideas is introduced as the new approach. Questions are provided for teachers to reflect on how to implement this construct-based assessment within their own subjects.