The Director of Human Resources Management shall apply the same rating system to all applicants who are determined to be eligible for competitive promotion or appointment to vacant positions in a particular class of work. The Director of Human Resources Management shall determine the appropriate use of nominal, ordinal, and numerical ratings and shall ensure sufficiency of the rating process. Where appropriate, the Director of Human Resources Management may apply an alternative rating system for particular positions in a class of work, including rating by minimum qualifications. Such determination must include a consideration of the critical nature of the vacancy(ies) and the appropriateness and uniformity of the criteria.