ارزیابی وب پورتال‌های کتابخانه‌های عمومی مستقر در استان تهران

Purpose: In this research, we aim to identify differences in important characteristics of the web portals of the Iran Public Libraries Foundation (IPLF) and Art and Cultural Organization of Tehran Municipality (ACOTM) according to the assessment criteria that extracted and formulated by researchers. Methodology: We used descriptive survey method. Participants include 646 librarians of IPLF and ACOTM. The instrument used for data gathering was a researcher-made questionnaire. Validity and reliability of questionnaire were measured and approved. Using random-classification sampling method, 242 questionnaires were handed out but only 170 of them were received and analyzed. In order to analyze data, we used SPSS and GAMS software. Findings: In the web portal of IPLF Information Navigation criterion was in the highest level and surprisingly the lowest score was recorded for Information validity criterion. Accessibility, accuracy, Coverage & Grouping users, Currency, quality and objectivity of information were situated in the next ranks. In the web portal of ACOTM, the highest score was recorded for Information Quality and the lowest score was recorded for Information validity conversely. Navigation, accuracy, coverage & Grouping users, Currency and accessibility of information were situated in the next ranks. Findings shows that promptitude diversity of navigation systems of IPLF web portal should accorded with validity and in ACTOM, quality of content should be accompanied with validity.  Originality/Value: In this research, we tried to show the critical measures of public libraries web portals and importance of validity criterion as an ignored measure.