Statistics has become an integral part of individuals' formal and everyday lives. Experiences that help learners make sense of statistical information are needed so that they can make informed decisions. The view of statistics as a decision-making tool can be emphasized in project-based environments, where students investigate problems that require formulating questions and collecting, analyzing, and representing data to address these questions. Producing investigations in collaboration with peers and presenting results to classmates require that students articulate the understanding that formed the basis of particular design decisions. We found that decisions in this context can be mitigated by factors (e.g., efficiency and social influences) that circumvent the appropriate application of principles (e.g., sampling) in the discipline or practices established in the classroom (e.g., use of criteria to assess peer projects) even though students understand them.