This report discusses the most relevant issues concerning using student test results in OECD countries. Initially the report provides an overview of how student test results are reported in OECD countries and how stakeholders in these countries use and perceive of the results. The report then reviews the literature relating to using student test results for accountability and improvement purposes. Two general findings can be drawn from the literature: (1) accountability based on student test results can be a powerful tool for changing teacher and school behaviour, but it often creates unintended strategic behaviour, and (2) no test can be a perfect indicator of student performance. Drawing from these findings the report discusses the advantages and disadvantages of using student test results for accountability and improvement. The discussion touches upon four themes: (1) assessment design, (2) the use of test results, (3) stakeholder involvement, and (4) implementation.