This paper describes the results of a study undertaken at the Iowa Sta
te University Libraries to evaluate the database tape products of thre
e companies. The ultimate purpose of the study was to choose and local
ly mount the database tapes of one general periodical literature index
on a NOTIS-based OPAC. The databases were compared and contrasted acc
ording to scope, duplication, gaps, depth of indexing, timeliness, for
mat, and subject coverage as well as other criteria.