Public organisations are characterised by high complexity, strong professional differentiation and multiple, sometimes competing logics of action. Communication problems arise less from a lack of participation than from unclear responsibilities, implicit expectations and missing closure after discussions. This reduces coordination quality, delays decisions and weakens implementation capacity.

The study is based on a qualitative case study conducted in a large public organisation. Semi-structured interviews with professionals from different functional and leadership roles were combined with the analysis of several cross-functional projects. The focus was on communication practices in decision-relevant situations, particularly regarding roles, mandates, coordination and communicative clarity.

The findings show that professional communication is perceived as effective when roles, decision authority and next steps are made explicit. Communication functions as a central mechanism for aligning different professional rationalities and enabling coordinated action. Influence and legitimacy emerge less from formal hierarchy than from the ability to structure information, translate perspectives and create temporary clarity that allows decisions to be implemented. For public organisations, the results indicate that improving communication does not require more communication, but clearer, role-sensitive and mandate-aware communication practices. The study derives concrete recommendations for leadership and organisational development that strengthen coordination at professional interfaces, reduce friction in cross-functional initiatives and enhance the implementation of complex public-sector projects.