Governments are under increasing pressure to deliver results. Therefore, it is important to evaluate the effectiveness, efficiency and relevance of the public service in implementing policies and programmes for social betterment. Without such evaluations, it is difficult to ensure that evidence is integrated into policy and used in practice due to lack of generalizability and learning. This paper focuses on (1) the knowledge that is relevant to understand evaluation influence, (2) the possible conceptual frameworks that enable understanding of the evaluation implementation process, (3) possible models of the process of organizational evaluation, and (4) the main ways of intervening to increase influence. The context for analysis is the South African Department of Agriculture.