The Internet is now firmly established as an environment for the administration, exchange and publication of data. To support this, a great variety of Web applications have appeared, among these web portals. Numerous users worldwide make use of Web portals to obtain information for different purposes. These users, or data consumers, need to ensure that this information is suitable for the use to which they wish to put it. PDQM (Portal Data Quality Model) is a model for the assessment of portal data quality. It has been implemented in the PoDQA tool (Portal Data Quality Assessment tool), which can be accessed at http://podqa.webportalquality.com. In this paper we present the various refinements that it has been necessary to make in order to obtain a tool which is stable and able to make accurate and efficient calculations of the elements needed to assess the quality of the data of a web portal.