Assessment data allows teachers to gauge the effectiveness of the lessons they are delivering and to improve their impact (Hattie, 2015). In order for teachers to make reliable conclusions about student progress, quality assessment measures need to be used (Masters, 2013). Quality assessments are those which provide valid, reliable, objective and inclusive measurements of student learning.

Assessment is most effective when it is an embedded part of the learning process. At a classroom level, assessment for learning (formative assessment) occurs when teachers seek and interpret evidence which helps them and their students to understand where they are in their learning, where they need to go next, and how to get there. This differs from summative assessment, which provides a statement of learning. Formative assessment means providing regular opportunities for students to demonstrate what they know in relation to the intended learning intention and receive thorough, timely feedback (Wiliam, 2017). 

Research shows a 0.75 effect size on student achievement when students receive constructive feedback as formative assessment (Beesley & Anthorp, 2010). When whole-school strategies are implemented in which teachers set common practices about reviewing and acting on formative assessment, the effect size on achievement is 0.96 (Wiliam, 2017). 

School level assessment data, generated from summative assessment, enables schools to understand where opportunities for improvement lie and where practice changes through better professional learning, coaching and additional support may be required. System level data, generated through standardised assessment, is an important tool for improving the design of supports in professional learning, instructional leadership, assessment and intervention across the system. 

Some standardised assessments, such as the Online Phonics Screening Check and NAPLAN assessments also support teachers to diagnose student prior knowledge and implement effective learning support and enrichment strategies.