There is an ongoing debate on what brought about the reduction in violence over the past three decades in high income countries but the phenomenon cannot be reduced to the application of a few societal programs. Attitudes to violence typically change slowly over time; examples are wife beating and corporal punishment of children. Programs aimed at reducing violence are thus unlikely to produce results quickly. In addition many programs have not been set up in a manner allowing rigorous evaluation. For many of these interventions we neither know their impact nor do we know their costs, thus making it impossible to provide BCRs.
Despite the uncertainty of what feasible targets for violence reduction are and how they can be achieved we advocate the inclusion of such targets in the post-2015 agenda. Our estimates suggest that the costs of violence are high; the welfare cost of collective, interpersonal violence, harsh child discipline, intimate partner violence and sexual abuse are equivalent to around 11 per cent of global GDP. The cost of homicides are much larger than the cost of civil conflict. However, violence perpetrated in the home appears to be the most prevalent form of violence. Domestic abuse of women and children should no longer be regarded as a private matter but a public health concern.
For more information, you can find this publication here : http://www.copenhagenconsensus.com/publication/post-2015-consensus-conflict-and-violence-assessment-hoeffler-fearon