Policy positions are used extensively to explain coalition formation, advocacy success and policy outputs, and government consultations and stakeholder surveys are seen as important means of gathering data about policy actors' positions. However, we know little about how accurately official consultations and stakeholder surveys reflect their views. This study compares advocacy organisations' publicly stated positions in their responses to official consultations with their positions expressed in confidential surveys conducted by the authors. It compares three decision-making processes in Switzerland – in energy, climate and water protection – to analyse responses via two different types of data gathering methods. The results show a substantial divergence between official and private expressions of policy positions. Specific types of policy actors (losers), instruments (persuasive measures) and subsystems (collaborative network) produce more divergent positions. This has important methodological implications for comparative policy studies that use different data gathering methods and focus on different policy domains.