This narrative literature review evaluates the effectiveness of synthetic phonics in comparison with analytic phonics. It presents the key research findings and offers a critical appraisal of this research. Primary schools have developed a variety of assessment processes which assess pupils' knowledge and skills in synthetic phonics. It is through using these assessment tools that gaps in pupils' knowledge and skills are identified and these gaps then form the basis of subsequent synthetic phonics interventions. The article concludes by arguing that a more detailed assessment framework may be required for the purpose of assessing children's reading development than the model which schools currently adopt.