Seeks to identify information interoperability protocols in 36 leading digital libraries to identify appropriate indicators.
Data gathering tool was a researcher-made questionnaire. Descriptive and inferential frequency, percentage, Lambda and Fisher's test were employed for analysis of data. Findings 29 (80%) libraries used OAI-ORE protocol, 6 (16%) university, school and special libraries used OAI-PMH protocol. Z39.50 more often used by national libraries. Public libraries used Z39.50 and SRU/W for better interoperability. Special libraries used protocols most and were more successful in Interoperability. School libraries rarely used any protocol.
The use of Z39.50 was influenced by the scope of library’s activity. Availability of archival resources and cultural objects (for example, museum objects) has led the libraries to use OAI-PMH for better interoperability. The use of Z39.50 and SRU/W was influenced by use of federated model in digital libraries. The use of OAI-PMH was influenced by the use of harvested model in digital libraries.