Progress is a powerful political concept, encompassing different and sometimes contradictory conceptions. This paper examines the results of a survey on progress conducted at the OECD World Forum entitled "Measuring and Fostering the Progress of Societies" held in Istanbul in June 2007. First, a distinction is drawn between the two approaches to progress (skeptical and optimistic) and four theories of progress (Liberal, Social Liberal, Green, and Conservative). Second, the survey results are examined in order to find the prevailing conception among the participants. Findings show that while the literature regards the Liberal, economically based theory of progress as sitting at the heart of the mainstream conception of progress, it is notable that, in fact, there emerged among the participants a different mainstream conception of progress: one that is optimistic in approach, yet both Social Liberal and Green in its theory.