The purpose of this study was to investigate the specific categories of documents and evaluate the application of  the five WH questions for achieving the plan and method of dissertation classification. To this end, bibliographic and metadata elements were used for organizing dissertations as categories to answer WH questions.Two methods of library and comparative survey were used in this research. Documentation review showed that many librarians have introduced new categories to organize their collections. Samples of these classifications were provided for a variety of information resource formats including music resources, archival resources, museum and art objects, maps, patent, periodicals, and more. Various designs have also been presented for different genres and subject areas, including literary, story and laws. Based on this research, 22 categories were identified to answer the five WH questions including 9 categories for answering the Who question, 7 categories for answering the What question and 2 categories for answering Where, When and Why questions. Categories were compared with metadata and bibliographic elements, blocks, and descriptive areas. As a result, the UNIMARC blocks and fields used to classify dissertations include 32 fields  and 4 blocks including descriptive information, notes, subject analysis and the responsibility of the work that are used to answer each question according to the related categories.The findings of the study confirmed that librarians need to design new classifications for a variety of formats, subjects and genres, although conventional classifications of documents were used in libraries. On the other hand, the bibliographic elements and metadata that have an important role in organization of dissertation can be used to answer the WH questions for the classification of dissertations. With this approach, dissertation is classified and available to users in the process of organizing and entering information in the software.