3) In-depth interviews with North Korean defectors The present survey is mainly based on face-to-face in-depth interviews with 17 North Korean defectors who have some experience with PPC. Witnesses were selected from those who had their experience with PPC after 2000. However, selected interviews also include such testimonies that are of particular importance or were not previously disclosed. The in-depth interviews were conducted based on a questionnaire, previously designed and developed by NKDB. Information was obtained systematically regarding real and actual conditions of the operation of PPC, the background and process that led to the witness’ detention in PPC, and the collection of data regarding the human rights conditions of prisoners in PPC. The North Koreans with experience in PPC were identified through the existing network of NKDB, the network of North Korean defectors, cooperation with the network of government organizations involved in the process of investigations of North Korean defectors upon their arrival in South Korea, as well as visits to Hanawon, the national orientation institute for North Korean defectors, and locations of witnesses. Interviews were conducted by experienced researchers from NKDB. 4) Consultations and workshops As the present survey is intended for a comprehensive and analytical report of PPC, disappearance, analysis abroad and the level of North Korea’s compliance with international human rights instruments, advice was sought from professional researchers on PPC, disappearance, the North Korean legal code and international laws. Advice given to us and the results of the survey were evaluated through private interviews with experts. The results of the evaluation were made public for comments and suggestions through the process of two open meetings and five separate workshops. Consultation with experts was maintained on a constant basis and the final results from this evaluation process have been reflected in this survey report. 34