In this paper, a UML profile for data quality is proposed with the aim of supporting quality improvement inside a single organization. The profile is based on the IP-MAP framework and has the advantage to give a formal definition to the main concepts related to the management of quality improvement, as well as to organize such concepts into a set of models useful to realize a software system. A methodology to improve data quality is also discussed. Specifically, a process to produce the UML artifacts designed by the data quality profile is specified and the initial steps of a pattern-based technique to design quality improvement are also presented.