Governmental agencies are faced with increasingly limited resources for developing, implementing, and especially monitoring environmental policies. Cost savings and increased effectiveness are, therefore, important elements of policy design. As a result, environmental agencies frequently turn to collaborative environmental governance. While theoretical work on effectiveness of collaborative environmental governance is abundant, empirical work examining its effectiveness is weaker. This panel addresses this gap by examining effectiveness in terms of outcomes and outputs. One of the claims made for collaborative management is that it allows and encourages different participants to contribute to the process in ways that utilize their particular skills and expertise. Soliciting input from, and devolving some sorts of authority to local governments and affected interests is said to allow local stakeholders, who are presumably better attuned to community needs, cultures and capabilities, to fine-tune regulations to the particularities of differently-situated constituencies. Yet, ability of local stakeholders to participate in these efforts differs across countries. Further, partnerships that are frequently developed to enable such collaboration themselves go through organizational stages that have varying impact on effectiveness. The first and third papers on this panel examine the above organizational/capacity impact from a comparative perspective. Further, the second paper addresses how new technologies can be employed to reduce costs citizens face when collaborating with state-level agencies in monitoring and reporting data. While many environmental policies require substantial time before measureable impacts can be detected, most policy evaluations are driven by policy agenda times. As a result, policy outputs are used a proxy for outcomes. The second and fourth papers explicitly address the relationships between policy outputs and outcomes, the former from a large-n, comparative perspective and the latter from the perspective of an in-depth path analysis. Papers on this panel examine collaborative environmental governance as it opens up a variety of possibilities to participants, some of which are conducive to increased cooperation and the achievement of good environmental outcomes, and some of which are not. Though collaborative environmental management is frequently seen as grass-roots approach, governmental agencies frequently play a role fostering these efforts. Two papers on this panel examine cases in which federal and state level governments initiated, enabled, or supported collaboration. While papers on this panel address environmental management challenges across a number of environmental issues (biodiversity protection, habitat protection, invasive species, and water quality), they all examine elements of stakeholder participation and its impact on the effectiveness of environmental management. Effectiveness is measured in terms of quality of governance (trust among stakeholders, stakeholder participation in monitoring) and outcomes (e.g., habitat protection, reduction of non-point pollution, and development of new rules regulating benefits from environmental resources).