Impact assessment of STEM initiatives in improving educational outcomes explores research evidence and labour market reports to show why successive governments think STEM education matters. It maps the policy background and the STEM crisis in the UK which led to the launch of the STEM informal education sector. These schemes funded by the government, educational charities and private organisations have now mushroomed at the local and national level. In the midst of so many activities for various age groups do we know what works or works better for specific group of students? Does one size fit all? The book provides a detailed report of a longitudinal national evaluation conducted in the UK by making use of official datasets. The activities evaluated here have not had a major influence on educational outcomes such as improved standardized national test results or increased STEM subject choices. The robust evaluation protocol described in this well-structured and thoughtful text will help schools to decide what works best for the students activity providers to evaluate long term outcomes for the activities they run researchers to replicate the protocol for similar activities in other settings Masters and PhD students understand how evidence from research can be used to inform policy and practice The results and implications combined with the recommendations made here will interest all those who are directly involved in the delivery of these enrichment and enhancement activities, practitioners using evidence, policy makers, the research community and schools wanting to run their own evaluations.