LOS CATÁLOGOS EN LÍNEA DE ACCESO PÚBLICO DEL MERCOSUR DISPONIBLES EN ENTORNO WEB.

User interfaces of web based online public access catalogs (OPACs) of academic, special, public and national libraries in countries belonging to Mercosur (Argentina, Brazil, Paraguay, Uruguay) are studied to provide a diagnosis of the situation of bibliographic description, subject analisis, help messages and bibliographic display. A cuali-cuantitative methodology is adopted and a checklist of systems functions created by Hildreth (1982) is updated and used as data collection tool. The resulting 38 closed questions checklist has allowed to observe the frequency of appearance of the basic functions of four areas: Area I -- operational control; Area II, search formulation control and access points; Area III, output control; and IV, user assistance: information and instruction. The study is carried out on the information obtained from 297 information units. Strata are delimited according to type of software, type of library and country. Chi square, Odds Ratio and multinomial logistic regression are applied to results. This analysis confirms the presence of significative differences according to the delimited strata and shows that most of the OPACs surveyed offer minimum capabilities. [ABSTRACT FROM AUTHOR]