Abstract: “Various studies have attempted to assess the amount of free full text available on the web and recent work have suggested that we are close to the 50% mark for freely available articles (Archambault et al. 2013; Björk et al. 2010; Jamali and Nabavi 2015). Our paper contributes to the literature by taking into account the timing issue by studying when the papers were made free. We sampled citations made by researchers who published in 2015 (based on records in the Singapore Management University Institution repository), checked the number of cited papers that were free at the time of the study and then attempted to “carbon date” the freely available papers to determine when they were first made available. This allows us to estimate the length of time the free cited article was made available before the citing paper was published. We find that in our sample of cited papers in Economics, the median freely available cited paper (oldest variant) was made available 7-8 years before the citing paper was published. Of these papers found free via Google Scholar, the majority 67% (n=47) was made available via University websites (not including Institutional repositories) and 32.8% (n=23) were final published versions.”