The need to understand ways of defining progression in history becomes ever more pressing in the face of a target-setting, assessment-driven regime which requires us to measure progress at every turn. We must defend our professional expertise in terms of measurable outcomes. Did we add value? Have our end of Key Stage levels improved? Have we met our targets at GCSE? Superficially, being able to measure ‘progress’ in these ways seems sensible. How else are we to monitor the performance of teachers, departments and schools against national benchmarks? But of course, as we have noted in previous editions, being able to produce simple, seemingly persuasive data is not, by itself, evidence that true progress in students’ historical understanding has actually occurred. Reaching Level 5 does not automatically define a student’s understanding of history as a discipline and it certainly does not capture the complexities that historical understanding entails. Project Chata (Concepts of History and Teaching Approaches) has, over a number of years, attempted to map changes in students’ ideas about history between the ages of seven and fourteen. In this article, the first in a series commissioned by Teaching History, Peter Lee and Denis Shemilt discuss the fundamental flaws in the current system of National Curriculum assessment and argue that other, research-based models of progression can be more helpful in our day-to-day planning and teaching. They do not claim any model to be perfect, nor indeed that what is most valuable in history - ‘the wisdom, perspective and understanding’ - can be captured in this way. They do, however, explore ways in which models based on empirical research - rather than on educational expediency - can be genuinely useful in understanding how to move students forward in their historical, understanding by identifying and clarifying the misconceptions which hold them back.