Since research and extension personnel have complementary roles in agricultural development, the success of each group is determined largely by the effectiveness of linkage activities. Even where the research and extension functions are located within one institution, linkages between them are not automatic. Therefore, appropriate mechanisms to strengthen linkages need to be developed. For developing such mechanisms it is important to understand the principles that determine the success of linkage activities. Six principles of linkage have been identified (Zuidema, 1989):
· a necessary condition for groups or institutions to participate effectively in linkage activities is that they should share a common purpose (i.e., domain consensus);
· the groups or institutions should perceive that it is advantageous for them to participate in linkage activities;
· there should be common ground or proximity of location between each group or institution to facilitate collaboration;
· linkage activities should be compatible with other activities of each group;
· there should be rewards for individuals participating in linkage activities; and
· communication between members of different groups should be effective and there should be free flow of information between groups.
Types of linkages
Four major types of linkages have been identified, based on ways of communication and channels of communication (Stoop, 1988).
'Formal' versus 'Informal' linkages Formal linkages refer to linkages that are specified and agreed to by organizations. Informal linkages are direct person-to-person contacts, based on the need for collaboration between individuals. Since informal linkage is an effective and low-cost method, it should be encouraged along with formal linkages.
'Top-down' versus 'Bottom-up' linkages In top-down linkage, information flows from scientists to extension and then to producers. Bottom-up linkages refers to the flow of information from producers to scientists. Information from farmers is based on their practical knowledge and helps improve the effectiveness of research programmes.
'Internal' versus 'External' linkages Internal linkages refer to linkages among scientists working in different disciplines and on different commodities, whereas external linkages are linkages with major clients, such as farmers, policy-makers, etc. External linkages help identify gaps in research priority and assess the utility of research programmes.
'Downstream' versus 'Upstream' linkages These linkages are a part of external linkages. Upstream linkages occur between research and policy making. The aim here is to secure adequate funding and political support for research. Downstream linkages occur between researchers and producers, to set research agendas and to establish priorities.