The omission of key conditions for meaningful public involvement can erect significant barriers to learning and may even threaten to hinder the maintenance of benefits and actions arising from the SEA and consequent learning outcomes. As Sinclair and Diduck (2001) note, while each deficiency decreases the opportunity for the full realization of positive learning outcomes, the presence of multiple deficiencies can create profound barriers to meaningful participation, learning, and by extension, action for sustainability. The deficiencies vary in each case, but a sufficient number of them are evident as outlined above. Together, these will likely collectively frustrate meaningful participation. Moreover, some insufficiencies may be interrelated or more critical than others. For example, the early opportunity to identify and assess future oriented alternatives and participant compensation are frequently under proponent control further limiting the opportunity for open dialog, debate, and learning.