Does double dipping occur? The case of Wiley's hybrid journals

The number of open access articles published in hybrid journals has increased recently. However, there are concerns over the practice of double dipping, when hybrid journals charge for publishing the same article twice, once for subscription and once for open access. To determine whether double dipping occurs, this study examined the relationship between the subscription prices for hybrid journals and the proportions of open access articles in hybrid journals. Two simultaneous equations of subscription prices and article processing charges for Wiley's 1141 hybrid journals were estimated using the full information maximum likelihood method. The results revealed that the increased proportions of open access articles did not result in lower subscription prices; thus, there is no denying that double dipping occurs. Furthermore, the article processing charges are affected by subscription prices, whereas subscription prices are significantly unaffected by article processing charges. The findings suggest that article processing charges rise in tandem with increased subscription prices; therefore, university libraries and consortiums must exercise caution when making subscription contracts with publishers.