Journal of Digital Information Management Hamid Reza Khedmatgozar, Mehdi Alipour-Hafezi 13 3 2015 In recent years, with the development of digital environment, one of the concepts that has been particularly important is digital identification of objects in this environment by digital identifier systems. The main objective of this study is to answer this important and basic question: How and on what framework can distinguish a digital object identifier system from other identifier systems? To achieve this goal, a comparative framework which consisted of 7 main characteristics of digital identifiers in three major domains (namely identifier features, digital coverage and comprehensiveness of scope) was proposed. Two major characteristics of the proposed framework are its inclusiveness and considering the differences between the uniqueness and persistency notions in general and in the digital environment. Then, an illustrative comparison of 23 well-known worldwide identifiers was carried out. Results of this study revealed that six identifier systems of DOI, Handle, UCI, ARK, URN and PURL can be regarded as the best choices of digital identifiers in public areas identified in the digital space and four identifier systems of ORCID, MIRIAM, ISNI and NBN are the best options to be used in certain specialized areas. These results can help information technology specialists to identify and effectively use of digital identifier systems in actual and potential practical areas.