Farrow et al (2015) report the results of a survey of over 3,000 OER users that used one of three repositories, namely iTunes U (110 responses), OpenLearn (725 responses), and Saylor Academy (2299 responses). The authors note that there was considerable geographic spread, as "Excluding Africa, only Bolivia, French Guyana, Greenland, Kyrgyzstan, Suriname, Turkmenistan, Uzbekistan, and Venezuela were not represented" (p. 55). Nevertheless, users in the US (862), the UK (473), India (117), Canada (87), and Brazil (84) accounted for over half of responses. The study finds that iTunes U has the lowest age profile of users, with 72% under 35 and over 30% under 19, followed by Saylor and then by OpenLearn, which has the oldest age profile (69% are over 34). The gender breakdown was approximately even between men and women for Saylor, although more men (56%) than women (44%) used iTunes and more women (60%) than men (40%) used OpenLearn. With regards to educational attainment, the authors note that "the general trend was that users of these platforms tended to report already holding a degree" (p. 57); 59% of Saylor users had an undergraduate degree, compared to 46% for OpenLearn and 38% for iTunes U. Furthermore, the study finds that 52% of Saylor users are employed (compared to 42% for OpenLearn and 30% for iTunes U), and 60% of iTunes U users were students (compared to 20% for Saylor and 11% for OpenLearn). Over 50% of users on all platforms reported accessing the materials on smartphones and tablets, and 70% reported accessing them through broadband at home. Across all platforms, 10% of users disclosed a disability. The study also finds that over 80% of the users on each platform accessed the OER for "personal interest" (p. 60). The next most common reason for access was professional development, which corresponded to 69% of Saylor users and around 50% of both iTunes U and OpenLearn users. The factor that most drew users to OER was "The opportunity to study at no cost" (p. 63), which corresponded to between 80 and 90% of users, depending on the platform. Two other appealing characteristics of OER were the ability to use it online and the ability to access at any time, both of which corresponded to between 60 and 75% of users depending on the repository. When selecting OER, users were most sensitive to relevance to their particular needs (70% identified this as an indicator for selection. They were also sensitive to clear learning outcomes (62%), reputation of creator (54%), and ease of download/access (52%). The major challenges encountered in using OER centered around locating resources that were subject specific (46%), that were high-quality, (36%), and up-to-date, (27%). Finally, the authors note that use of OER had mixed effects on users' propensity to study formally. For iTunes U, 23% of users were more likely to study formally and 25% were less likely to do so, compared to 20% and 20% for Saylor Academy. For OpenLearn, 31% of users were more likely to study formally and only 14% were less likely to do so; the authors suggest this "may be explained by the existence of planned pathways between OpenLearn content and degree level content provided by The Open University" (p. 69).