In response to the rapid development of digital libraries over the past decade, researchers have focused on the use of metadata as an effective means to support resource discovery within online repositories. With the increasing involvement of libraries in digitization projects and the growing number of institutional repositories, it is anticipated that metadata will play an even bigger role in the retrieval and dissemination of resources in the near future. Empirical findings, however, reveal various kinds of errors in metadata records that affect their utility. Researchers acknowledge these problems and theorize that the lack of adequate guidelines and inadequate metadata creator training could be possible sources of errors in the records; so far no attempt was made to investigate these claims. A mixed factorial design experiment was conducted in which 120 participants were assigned to four groups on the basis of their training level and the kinds of information (definitions only or definitions plus best practice guidelines) accessible to create metadata records. Participants created records for the same resources and errors were analyzed and compared across groups. Results presented here show that although the effects of training and best practice guidelines vary with the resource and the kinds of errors investigated, both training and best practice guidelines are important factors that need to be considered in order to minimize errors in metadata records. The study concludes that more research is required before a comprehensive understanding of the causes of metadata errors can be established. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]