in addition to the required substantive competence, gender balance and geographic diversity must be given due consideration. When staff are seconded to the secretariat from other United Nations entities, they must be fully integrated into the team and subject to the same reporting lines as all other staff for the duration of their assignment. The independent and impartial conduct of the secretariat, and perceptions thereof, are as important as those of members. All members of the secretariat – whether OHCHR staff, seconded staff from other United Nations entities, externally hired staff or consultants – are required to undertake to always act independently and impartially and to respect, during their tenure with the commission/mission and afterwards, the confidentiality of all information gathered or accessed in the course of the work of the commission/mission, to ensure the security of such information and not to share it with anyone outside of the commission/mission except if duly authorized according to United Nations rules (see chap. IV, sect. C.6, Informed consent). 2. SECRETARIAT STAFF While, as mentioned above, the size and composition of the secretariat may vary, there are certain professional profiles that are necessary to fulfil the mandate of all commissions/ missions. Most functions can usually be performed by OHCHR staff or by staff of other United Nations departments. Some may require expertise and skills that may not be available within OHCHR or the United Nations and it may thus be necessary to recruit staff or consultants from outside (staff, if the expertise is required on an ongoing basis; consultants, if required for contained or one-off tasks). The coordinator/head of the secretariat/chief of staff Must have strong substantive human rights expertise as well as developed management skills and a proven ability to handle complex and sensitive assignments. Political awareness and diplomatic skills are also important. Investigation team leader Must have proven ability in planning and managing complex investigations, with knowledge of international human rights law and/or international humanitarian law and/or international criminal law, depending on the scope of the mandate. Human rights investigators Must have proven ability to handle complex human rights fact-finding and investigations. They should have extensive investigations experience and be fully trained in human rights investigative methodology. Investigators specialized in specific human rights issues, for example sexual violence, may be required. GUIDANCE AND PRACTICE 23