-54 best practices, rather than on problems and what is not. As Liebling describes it: ‘We found, through this method, that we could dig deeper into a prison, if we were sensitive to people’s achievements as well as to their problems and difficulties.’98 For these reasons, the appreciative inquiry method could be an efficient tool to better understand and monitor the prevailing climate and the quality of life in a prison, but also identify practices for solution oriented recommendations (see also below §5, and in this series the Dossier). 4.3.3. Review of prisoner files, documentation and registers Prisoner files (electronic/paper) and the documentation of measures taken shall be reviewed to assess whether the decision-making process can be justified and all relevant information was documented. Prisoner files could be used during interviews with prisoners for further inquiries, especially regarding any violent incidents in which they were involved. Registers and reports of incidents (violence, self-harm and suicide attempts, use of force), CCTV and (if used) on-body camera footage and registers of disciplinary measures are of particular importance. These resources may provide detailed information on the prevalence and type of violence or violation, the prison guards involved in it as well as the time and the location of incidents, all of which may be used to identify patterns of violence and possible structural deficiencies. NPMs should inquire whether prisons compile such statistics and have internal procedures in place to identify lessons learned after every serious incident. Other relevant sources are medical files, especially records of injuries. Therefore, NPMs must review medical files, but also inquire with medical staff to see if they are aware of their obligations concerning the documentation of signs of potential ill-treatment. Additionally, the review of requests and applications of prisoners as well as of complaint registers, especially for those prisoners who were involved in any form of violence, could indicate whether the duty of 98. Alison Liebling and others, Appreciative Inquiry and Relationships in Prison, Punishment and Society (1999)1(1) The International Journal of Penology, 71-98.