. Data quality. It is very difficult to say what data quality means. The word quality itself has different meanings to different people. Even for an individual the word can have a different meaning depending on the circumstances. I'll use an example to try to make it clearer. If we ask three people to tell us which car they think is a quality purchase, we will get three or even more different opinions. Some will say acceleration is important, others will say safety. Some would prefer an environmentally friendly car, others a low-priced one. This is why there is no universal agreement on what data quality means, so few definitions exist. In my opinion, Joseph Moses Juran's definition is the most representative and summarizes most of the existing definitions. According to Joseph Moses Juran “Data is of high quality if it is suitable for its intended uses in operations, decision making and planning” [1]. So how do we know if our data is of good or bad quality? Following the example of the car, to answer this question we must define which characteristics we must take into consideration and how much each of them weighs. It is also important that these characteristics are measurable. Continuous research in this field provides us with a wide range of data attributes along with a ranking, based on their importance. In the data quality literature these attributes are referred to as dimensions. From now on we will use this term when talking about data quality characteristics. In chapter 2.2 we will present the dimensions of data quality in detail. 2.1 Why good data quality is essential. In 2006, Clive Humby, a Sheffield mathematician, stated that "data is the new oil", in an attempt to highlight the importance... .... half of the paper ......as "the heterogeneity of their components" and safety issues.d. The IS cooperative. According to Massimo Mecella et al. “it is a large-scale information system that interconnects various systems of different and autonomous organizations, sharing common objectives” [30]. The main problems with these information systems are the numerous copies of the same objects (duplicate copies) and the possibility that poor quality of data from one source spreads through cooperative systems. It is therefore very important that individual information systems are reliable. The Web IS. The importance of the web has led classic information systems to transform to integrate with web technologies. This means that a web application can access an organization's dataset. And as mentioned above, this integration creates new data issues, such as security and accessibility.f. P2P IS.