This study investigated and compared the proportions and trends of coauthored articles by practitioners in the three fields of computer science, library science, and management. The primary practitioners writing articles in these three fields were engineers, librarians, and consultants, respectively. Practitioner authors were scarce, however, in computer science and management. The author of this study analyzed articles published in nine selected journals in each field indexed by Journal Citation Reports between 2005 and 2014. The proportions of articles in library science coauthored either by practitioners only--that is, by librarians--or by both practitioners and researchers were considerably higher than those in computer science and management. Articles coauthored by practitioners and researchers in computer science increased slightly over the study period, whereas such articles decreased slightly in both library science and management.