1. A computer-implemented method, comprising: obtaining data describing a plurality of medical image studies from at least one medical data server, the plurality of medical image studies pending examination; determining a relative complexity value for each medical image study using a quantity of relative value units that are based at least in part on an average amount of time to perform a particular type of image study associated with individual ones of the plurality of medical image studies; assigning each of the plurality of medical image studies for examination by a respective user of a plurality of users based at least in part on preferences associated with the respective user and the relative complexity value determined for each medical image study; causing a user interface to be rendered by a client device, the user interface including a respective user worklist tab for each of the plurality of users, the respective user worklist tab showing an identifier of the respective user, the respective user worklist tab displaying a listing of medical image studies that have been assigned to the respective user for examination, the user interface further including a pending tab displaying a listing of medical image studies for which examination is pending and that are assigned to any of the plurality of users; and preventing a user from viewing a particular medical image study based at least in part on a lock status associated with the particular medical image study that indicates that the particular medical image study is being viewed by at least preventing access to image data associated with the particular medical image study stored in a data store.