-59 2. Accuracy. The principle of accuracy requires that the monitor checks the information received with as many sources as possible before assessing the evidence and deciding which one he/she wants to include in the report or the recommendation. It also requires that the monitor always prefers first-hand information, rather than hearsay. The monitor should be aware of the biases of his/her sources, as well as their own. In the unfortunate case where an error is uncovered in the monitoring report or in other public statements, it is always preferable to recognize it. 3. Impartiality. The key requirement of the principle of impartiality is sticking to one’s institutional mandate. In a detention, as well as in other contexts, it also means talking to all sides and being even-handed in addressing the responsibility for human rights violations of different parties. NPMs should develop a policy of impartiality, part of which should be ensuring political, ethnic, religious and gender diversity in the composition of monitoring teams. It is a good practice among some NPMs to involve persons who belong to vulnerable groups as members of the monitoring team. Developing country-specific concepts and approaches to vulnerability by NPMs are also aspects of impartiality. 4. Confidentiality. The principle of confidentiality is based on two rationales – the protection of the private life of everybody targeted by the research, and the protection of the safety of the vulnerable sources of information. It requires constant assessment of whether and why the monitor needs to cite names and details of the personal circumstances of the individuals involved in the research, ensuring that the source (whose safety may be compromised) is not traceable by the authorities, keeping contacts with vulnerable sources of information after the publication of the findings, and establishing a system to store confidential information in one’s office. It is always a good practice to discuss confidentiality with other members of the monitoring team, and get a second opinion. 5. Transparency. This principle is somewhat opposite to confidentiality. It is based on different presumptions, the major one of which is that the researcher’s approach to information-gathering should avail itself to public scrutiny. Methodological transparency underlines every social research initiative, but in monitoring closed institutions and the situation of groups and persons in a situation of vulnerability, it has limited application as it may expose them to danger. Yet, clarifying entirely the monitor’s goals and methods should be a must even in such circumstances. Whenever possible and harmless, he/she should cite sources, and explain in some detail the reasons why this may not be possible in certain circumstances. Offering peer-assessment of Prisoners in a Situation of Vulnerability