All agencies shall select from the pool of the most qualified persons to fill vacant positions. Employment shall be offered based upon the job-related qualifications of applicants for employment using fair and valid selection criteria and not on political affiliation or political influence. Nepotism is not permitted. The selection of applicants for vacant positions shall be based upon a relative consideration of their qualifications for the position to be filled. Using fair and valid selection criteria, the agency shall review the credentials of each applicant and determine who possesses the minimum qualifications. From those applicants who meet the minimum qualifications, a pool of the most qualified candidates shall be identified. The pool of the most qualified candidates shall be those individuals determined to be substantially more qualified than other applicants. The individual selected for the position must be chosen from the pool of the most qualified applicants. Selection procedures and methods shall be validly related to the duties and responsibilities of the vacancy to be filled.