In Sweden, efforts to achieve environmental sustainability have been canalised through a system of management-by-objectives (MBO), including sixteen national environmental quality objectives. In the process of monitoring and assessing progress towards the environmental objectives, communication of scientific information is a crucial component. While management literature emphasizes well-functioning communication as a prerequisite for successful MBO, empirical studies have shown that communication problems and misunderstandings are likely to arise in the dissemination, implementation and assessment of visionary objectives at different levels in the environmental bureaucracy. Thus, there is a need to further identify and discuss obstacles in the communication process, focusing on the information flow between the scientific community and the environmental bureaucracy. In the paper, I discuss prerequisites for communication between scientists, practitioners and policy makers involved in the assessment of environmental goal achievement. I take my point of departure in the communicative context at hand when communicating progress towards the national environmental objective -Zero eutrophication-. The paper is based on analyses of policy documents on the environmental objectives, and individual and focus group interviews with key actors within the environmental bureaucracy and scientists developing statistical tools for the assessment of progress towards environmental objectives. When scrutinizing the communicative context at hand when results from the environmental objectives are communicated, it is obvious that all parts of the communicative chain could be problematized and are not always clear to the actors involved in the communicative situation. Thus, I argue that in the efforts to communicate messages related to the assessment of environmental objectives, there is a need to return to the following five fundamental questions: - WHY should assessment activities take place? - WHAT should be assessed? - HOW should assessment be effected? - BY WHOM should assessment be effected? - TO WHOM should the assessment methods and results be communicated? In the paper I discuss the questions above, taking my point of departure in the interview data and the analysis of the policy documents. I also discuss different models for communicating results of the assessment of progress towards the objective -Zero eutrophication-. In this discussion, dialogical and participatory aspects of communication are emphasised.