All requests for public or commercial use and translation rights should be submitted to rights@oecd.org. It presents an overview of how different OECD countries allocate instruction time. It also develops a model to understand the effective use of allocated instruction time and examines how different OECD countries compare on this. The paper confirms the value of sufficient instruction time as a key educational resource, but the key conclusion is that what matters the most is the way in which allocated time is used.