We describe an investigation of the support that three different display configurations provided for a collaborative sensemaking task: a digital table; personal tablets; and both the tabletop and personal tablets. Mixed-methods analyses revealed that the presence of a digital tabletop display led to improved sensemaking performance, and identified activities that were supported by the shared workspace. The digital tabletop supported a group's ability to prioritize information, to make comparisons between task data, and to form and critique the group's working hypothesis. Analyses of group performance revealed a positive correlation with equity of member participation using the shared digital table, and a negative correlation of equity of member participation using personal tablets. Implications for the support of sensemaking groups, and the use of equity of member participation as a predictive measure of their performance are discussed.