Civil Service Personnel Rule 31
31. Promotion shall be carried out in accordance with the following principles:
(a) aiming to improve the efficiency of the relevant service personnel organization;
(b) specifying the required minimum educational qualification and skills for the post;
(c) considering only the service personnel within the department who meet the specified qualification for the post to be promoted;
(d) promoting the most suitable service personnel according to the assessments of the qualifications and skills.