repository, it is possible simply to continue with the existing economic model. This is because, at present, there is no evidence that green open access encourages institutions to cancel subscriptions, even in high-energy physics where the practice has been common since 1991.47 Of course, this could change in the future (as posited by one much-criticised study48) and it may be that there is disciplinary variance, so caution is advisable. It is also unknown how this model could work in the monograph sphere, although this is covered more thoroughly below. A further study commissioned by the Association of Learned and Professional Society Publishers, however, also showed that there are many more important factors that determine subscription cancellation than green OA.49 This study covered a broad range of subjects, including science and technology, medical and healthcare, humanities and social sciences, and business and management. However, the study found no discernible disciplinary differences for the reasons why librarians would cancel subscriptions; in all cases, green OA came well below pedagogical and research relevance, the level of usage and the price. As Peter Suber’s analysis of this study puts it: ‘toll-access journals have more to fear from their own price increases than from rising levels of green OA’.50
The reasons why green open access doesn’t cause subscription cancellations are not wholly understood but must at least partially be attributed to the fact that green OA versions are often not on par with their version-of-record counterparts. Indeed, at the current permitted levels of deposit there would still be a hierarchy of access in which paginated, final versions of record, without embargo, could only be guaranteed to those at wealthier institutions. It is also true that the current rate of deposit, even when allowed by publishers, does not give substantial coverage due to the lack of institutional incentives (academics simply don’t see the advantages of depositing to themselves).51 Furthermore, green open-access versions often do not appear in traditional library discoverability search routes (although they may fare well in proprietary rankings, such as Google), which could contribute towards a continued perceived need among faculty for a subscription. Finally, the length of necessary embargo periods to maintain subscription rates is disputed. The UK’s House of Commons Business, Innovation and Skills (BIS) Select Committee Inquiry concluded that there
