Design research projects can be characterized as iterative and theory based attempts simultaneously to understand and improve educational processes. To contribute to a framework for design in statistics education, this paper draws on two design research projects, one carried out by Cobb, Gravemeijer and colleagues in the United States and one by Bakker and Gravemeijer in The Netherlands, both focusing on distribution as a core concept in the instructional design. Both projects were inspired by the theory of realistic mathematics education, which includes design heuristics such as guided reinvention, historical and didactical phenomenology, and emergent modeling. Each of these heuristics is briefly illustrated with examples from these two projects.