This study identified four different categories of intellectual outcomes reported by long-term research collaborators, adding insight to different approaches collaborators use to construct theory. Members of 19 collaborative pairs were interviewed. Each pair included at least one member with the rank of associate or full professor at a research university. Thirteen pairs earned doctorates in the same academic discipline; six pairs earned doctorates in different disciplines. The four categories of responses that emerged were: (1) efficiencies of practice; (2) nuance in thinking; (3) coming up with the big picture; and (4) challenging the gospel. For 7 of the 19 pairs, efficiency gained through combined efforts was the outcome most frequently mentioned. Members of five pairs described advances in thinking, or sharpening thinking through collaboration as the primary outcome of collaboration. Almost all participants pointed to the impact of collaboration on the quality of the work produced. Findings suggest a number of ways to operationalize the outcomes of a body of work that could provide a framework to assess quality of a publication or body of work in terms of its contribution to knowledge. (SLD)