Is the collaborative service always superior to the single library service?

With the development of the digital reference service, more and more single service institutions have been involved into consortia to participate in the collaborative online reference service. Nevertheless, to some extent it is still questioned whether the collaborative service is always superior to the single service. This paper reports a student research project that gives a reply to this doubt. During the project, the chat reference services provided by four categories of libraries in the United States were evaluated. At first, the author describes the origin, scope, methodology and limitations of the project. Then the workflow is briefly introduced step by step. Later some important results created from the project will be summarized. At last, the author draws conclusions including the advantages and disadvantages of both the collaborative and single library chat reference service and the experiences and lessons achieved from the project. [ABSTRACT FROM AUTHOR]