The names that appear at the beginning of a paper serve one important 
          purpose. They let others know who conducted the research and should 
          get credit for it. It is important to know who conducted the research 
          in case there are questions about methods, data, and the interpretation 
          of results. Likewise, the credit derived from publications is used to 
          determine a researcher’s worth. Researchers are valued and promoted 
          in accordance with the quality and quantity of their research publications. 
          Consequently, the authors listed on papers should fairly and accurately 
          represent the person or persons responsible for the work in question.
        
      Contribution. 
          Authorship is generally limited to individuals who make significant 
          contributions to the work that is reported. This includes anyone who:
        
          -  was intimately involved in the conception and design of the research,
-  assumed responsibility for data collection and interpretation,
-  participated in drafting the publication, and
-  approved the final version of the publication.
 There is disagreement, however, over whether authorship should be 
          limited to individuals who contribute to all phases of a publication 
          or whether individuals who made more limited contributions deserve authorship 
          credit.
        
 The widely accepted Uniform Requirements for Manuscripts Submitted 
          to Biomedical Journals, authored by the International Committee of Medical 
          Journal Editors (ICMJE), sets a high standard for authorship. It recommends 
          limiting authorship to persons who contribute to the conception and 
          design of the work or to data collection and interpretation and, in 
          addition, play an important role in drafting and approving the final 
          publication. Anyone who plays a lesser role can be listed under acknowledgments 
          but not at the beginning of the paper as an author.
        
 As influential as they are, the ICMJE recommendations on authorship 
          are not uniformly followed, even in journals that subscribe to the ICMJE 
          Requirements. Practices for determining authors vary considerably by 
          discipline and even from laboratory to laboratory. This places most 
          of the responsibility for decisions about authorship on the researchers 
          who participated in the work reported in each publication. These decisions 
          are best made early in any project, to avoid misunderstandings and later 
          disputes about authorship.
        
      Importance. 
          Authors are usually listed in their order of importance, with the designation 
          first or last author carrying special weight, although practices again 
          vary by discipline. Academic institutions usually will not promote researchers 
          to the rank of tenured faculty until they have been listed as first 
          or last author on one or more papers.
        
 As with the principle of contribution, however, there are no clear 
          rules for determining who should be listed as first author or the order 
          in which other authors should be listed. The ICMJE Requirements simply 
          note that:
        
 The order of authorship on the byline should be a jointdecision of 
          the coauthors. Authors should be preparedto explain the order in which 
          authors are listed.
        
 Some journals have specific rules for listing authors; others do not, 
          again placing most of the responsibility for this decision on the authors 
          themselves.
        
      Corresponding 
          or primary author. Many journals now require one author, 
          called the corresponding or primary author, to assume responsibility 
          for all aspects of a publication, including:
        
          -  the accuracy of the data,
-  the names listed as authors (all deserve authorship and no one 
            has been neglected),
-  approval of the final draft by all authors, and
-  handling all correspondence and responding to inquiries.
 In accepting this responsibility, corresponding authors should take 
          special note of the fact that they are acting on behalf of their colleagues. 
          Any mistakes they make or fail to catch will affect their colleagues’ 
          as well as their own careers.