Interest in the nature of the relationship between planning and performance is long and enduring (MacMillan & Narasima, 1987; Miller & Cardinal, 1994; Perry, 2001; Rudd et al., 2008) yet the merits of this idea remain the subject of intense debate and criticisms focusing on the inconclusive nature of previous bi-variate empirical findings. This study examines how business plan formality and entrepreneurial team size influence revenue expectations, gestation activities, and expectation revisions in nascent ventures. We study both the direct effects, as well as moderating effects, of the formality of business planning efforts and team size on these outcomes. Our central hypothesis is that whereas formality and team size add information, coordination, and knowledge benefits that enhance progress through the nascent stages of venture creation, revenue expectations may be adversely influenced by concurrent groupthink dynamics.