Purpose: Scholars agree that evaluation of participatory action research is inherently valuable; however there have been few attempts at evaluating across methods and across interventions because the perceived success of a method is affected by context, researcher skills and the aims of the participants. This paper describes the systematic evaluation of participatory action research with 17 European networks (LINSA) as part of a research project titled SOLINSA: Support of Learning and Innovation Networks for Sustainable Agriculture. Methodology: Participatory action research was carried out over three years in collaboration with the 17 LINSA using a learning-oriented evaluation that was adapted to SOLINSA. The collaboration was evaluated using a structured evaluation instrument that was developed in the project. Findings: The primary achievements of the interactions were based around enabling LINSA to reflect on their state and their practices. Joint reflection; facilitated by a member of the research team and in collaboration with the LINSA, stimulated internal engagement, enabled rethinking of the network's positioning, contributed to strategy development, and enabled creation of concrete outputs. Participation in the reflection process served to encourage commitment to the LINSA by individuals while improving relationships within the LINSA. Researchers and participants expressed that collaborative action research can be considered successful when both parties give and gain benefits, such as new knowledge or improved practical solutions. Practical implications: Comparison of self-evaluation of different networks using a single tool enabled the identification of common factors that contribute to successful collaboration. Included in these common factors was the need to identify and build a working relationship with key partners based on mutual trust and commitment, and to gain a balance between guidance and listening, interactions and freedom, and positive and critical reflection: a fragile equilibrium that is difficult and time consuming to establish. Originality: The adaptation of learning-oriented evaluation, by including a structure to allow comparison between the wide range of contexts, provides a useful instrument for evaluating participatory action research processes.