26. Public administration and the civil service should mainstream diversity in the structures and mechanisms of their work, including by employing persons belonging to minority groups, especially where the delivery of essential services is concerned. They should also mainstream diversity in the substance of their work. In order to promote integration, public administration should, to the extent possible, reflect the diversity of society.62 States should identify ways of promoting the recruitment and retention of persons belonging to minorities in the public sector. Special attention should be paid to achieving an adequate presence of persons belonging to minorities in sectors that provide essential services. These include, inter alia, the judiciary, law-enforcement bodies, social welfare and healthcare institutions, and education institutions. Defining targets for representation and a time schedule for achieving them is a practical way for governments to achieve adequate representation. However, while quotas can be useful in certain exceptional circumstances, rigid quota systems with exact proportions or specific posts for a particular group are usually to be discouraged. Over time, they limit flexibility and can potentially create new inequalities, and may prevent the public service from adapting to changing circumstances in society. Mainstreaming a diversity policy in the public sector implies that the composition and promotion of staff at all levels of public administration should be monitored to prevent direct or indirect discrimination. It also entails ensuring that everyone in the public sector understands the objectives and the policies to promote integration, and that they consider the implications for integration when designing and implementing policies. Public education institutions and public media have important roles to play in the formation of understanding and support for integration. 62 34 Commentary on Participation, paragraph 120. Guidelines on Integration of Diverse Societies