In almost all cases, though, the selection of a minister for the congregation is, in keeping with the Reformed tradition of the "priesthood of all believers", vested in a congregational meeting, held usually after a special "ad hoc" committee searches on the congregation's behalf for a candidate. Members of the congregation vote for or against the committee's recommended candidate for the pastorate, usually immediately after the candidate has preached a "trial sermon;" candidates are usually presented one at a time and not as a field of several to be selected from. Typically the candidate must secure anywhere from 60 to 90 percent affirmative votes from the membership before the congregation issues a formal call to the candidate; this depends on the provisions in the congregation's particular constitution and/or by-laws.