The numbers matter. Without clear and accurate data, women's experiences of violence are written out of the story on British crime, and policy decisions on how to respond to domestic violence are made based on only half of the picture. How do we develop appropriate and effective responses to a crime we do not fully understand? We need to get to the bottom of why in 2015 thousands of women and children are still being traumatised and brutalised in their own homes. We need to understand why women and children are still being killed and killing themselves to escape domestic violence.