Policy-makers and practitioners in education generally say that they want, and would use, good evidence. However, only a minority of teachers actually incorporate evidence-led practices into their lesson plans or guidance for pupils. Despite improvements, an important barrier preventing the widespread use of high-quality evidence is the lack of high-quality evidence to be used, caused chiefly by the lack of research competence or interest among so many researchers whose job it is to provide evidence in education. In order to use evidence to inform policy, policy-makers would need a range of skills and knowledge that they usually do not possess – such as the ability to source, evaluate and use evidence. The use of evidence is also obstructed by factors such as political promises, expediency, personalities, personal relationships, available funding, marketing by vested interests, self-interest, public opinion, and ideology.