To advance understanding of the motivational dynamics by which, in the very early stages of entrepreneurial pursuits , some individuals get sufficiently excited by a new venture idea to examin e it further and engage into more entrepreneurial efforts, it is theoretically important to not only study the influence of individual dispositions and circumstantial dynamics, but to also capture the effects of early - stage beliefs about these ideas . In o rder to foster research in this area, we conduct a series of studies to assess the validity and effectiveness of a new instrument targeting people’s early-stage opportunity beliefs.