The main aim of this research was to investigate the impact of reducing the number of components on overall performance in GCSE subjects. In particular, researchers were interested in how the grade achieved by candidates on a reduced number of components compares to their grade on the full qualification. This research mainly looked at GCSEs with three components and the impact of reducing this to two. Researchers also looked at the two combined science GCSEs (which have six and four components respectively) and the impact of reducing the number of exams to three in each case. The full list of subjects included in the analysis is: Citizenship Studies; Drama; Geography A; Geography B; Music; Mathematics; PE; Combined Science A; and Combined Science B. In Maths, findings show that around 85% of candidates would have received the same grade if the number of components was reduced from three to two. The percentages achieving the same grade were lower for other subjects. In other subjects, different components were more likely to examine different topics, which may lead to less consistent performance across components, and therefore more possibility of differences in grades.