Informatica Economică vol. 16, no. 1/2012 87 The PQUAL Open System Quality Model Cristian IONIŢĂ Academy of Economic Studies, Bucharest, Romania crionita@ie.ase.ro Quality assessment of open business enterprise systems is very important because those plat- forms play a central role in the organizations that implement them. The current paper pro- poses a new easily applicable software quality model called PQUAL that evaluates the quali- ty of such systems. The quality characteristics are identified and analyzed using the ISO/IEC 9126 international standard as a starting point. The paper develops metrics to measure the quality level for the characteristics. The PQUAL model is applied to compare the quality of the DocuMentor and YAWL platforms. Keywords: Quality, Model, Metric, BWL, BWS, Evaluation, Open Business Enterprise System Introduction Modern businesses employ complex business processes that involve documents, people and internal or external information systems in order to perform their activities. These processes can be automated efficiently by using open business enterprise systems – OBES. An OBES is an integrated set of sub- systems that support operations, management and decision making, composed of three ex- tensible subsystems: client - allows the final user to interact with the data and business processes managed by the system, processing - implements system operations, manages process instances, exposes its functionality to the external systems using a well-defined in- terface and storage - stores the data manipu- lated by the business processes using a user defined structure. An OBES architecture called BWS and the DocuMentor platform that implements it are presented in [1]. Because every OBES plays a very important role inside the organization where’s imple- mented, assessing its quality is critical. The quality of a software product is defined as the set of characteristics that allows it to meet the expressed or implied needs of the users. A quality characteristic is a set of properties of software by which the quality can be de- scribed and assessed. Characteristics can be decomposed into several levels of sub fea- tures. Generic quality standards such as ISO / IEC 9126 represent starting points for defining specific quality assessment models. The de- velopment of a specific quality model is use- ful for both the developer (to determine com- petitive advantages) and the client (for prod- uct selection). The quality model reveals the complex inter- dependence, subordination, decomposition and aggregation relationships existing be- tween the quality characteristics. According to [2], in order to be functional, a quality model must satisfy the following require- ments:  complete: address all aspects relevant to quality;  hierarchic: the characteristics must be de- composed in sub elements quantifiable us- ing metrics;  consistent: the characteristics mustn’t con- tradict one another. The ISO/IEC 9126 standard defines six char- acteristics that describe, with minimal inter- dependencies, the product quality. The char- acteristics proposed by the standard are: functionality, reliability, efficiency, usability, maintainability and portability. The standard model is a generic one, suitable for a vast array or software products. In order to be used, the model must be adapted for the specific software category. The PQUAL model was developed with the specific goal of measuring with minimal ef- fort on part of the model user the quality of open business enterprise systems. It measures the usefulness of an OBES platform as a business process automation and optimiza- tion tool inside the enterprise. 1