Participation equality, a prominent construct that has received much attention in group decision making research, has been studied with both perceptual and objective measures. Yet research findings regarding participation equality have been inconsistent and equivocal. We argue that one reason for this inconsistency is how participation equality has been conceptualized and measured. In some studies, researchers have theorized and measured participation equality using observed behavior. In other studies, researchers have theorized and measured participation equality using perceptual measures. We conducted an experiment to investigate the similarities and differences between these two measures. Our results indicate that 1) perceptual participation equality (PPE) and observable participation equality (OPE) are theoretically separate and distinct constructs that 2) affect and are affected by other constructs in different ways within their nomological network. OPE and PPE were more different than they were similar, sharing only 10.8% of their variance. In other words, perceptions of participation equality were predominantly influenced by factors other than observed behaviors related to participation equality. We believe these results call for more theory and research regarding the differences between observable behavior and perceptions of behavior in group decision making. As we move into new computer-mediated communication technologies such as Web Conferencing, Virtual Reality, and Enterprise Social Media that enable new forms of participation, we need to consider what constitutes participation and how new forms of participation should be measured and evaluated. In the large group environments of Enterprise Social Media, the differences between OPE and PPE are likely to become more pronounced.