“The United Nations frequently engages experts under individual contracts to work on short-term projects either as a consultant or an individual contractor”.
A consultant is a recognized authority or specialist in a specific field, engaged by the Organization in an advisory or consultative capacity. The functions of a consultant are results-oriented and normally involve analysing problems, directing seminars or training courses, preparing documents for conferences and meetings, or writing reports on matters within their area of expertise.
An individual contractor is engaged by the Organization to provide expertise, skills or knowledge for the performance of a specific task or piece of work, which would be short-term by nature. The assignment may involve full-time or part-time functions similar to those of staff members.”
Fonte e mais informações: careers.un.org