There is a shortfall in data needed to accurately analyse the scale of the problem and identify policy solutions. In line with our Principle 4, the government should commission a large-scale research project into how far social media recommendation systems spread, amplify or prioritise harmful content. This should be undertaken by a group of credible independent researchers, bringing diverse perspectives, with full access to the inner functions of the systems that major platforms use to algorithmically recommend content, including the private, external, and third party data used to train their systems; the user, content and engagement attributes the algorithms rely on and how these are weighted, and the objectives the algorithms are optimised for; where user interactions reinforce future recommendations; and any curation rules or interventions that influence promotion or suppression of content. We expect full cooperation from all major services that employ recommendation algorithms. (Recommendation, Paragraph 29)