# On the Use of Quality Models to Address Distinct Quality Views
## 4 Results  
This section presents the taxonomy of the software product quality model families from the point of view of quality manifestations they can capture. An important aspect of the quality models is their ability to measure the properties of software products; therefore, software product quality models are involved in the study; however, some quality models also exhibit properties to assess the process by which the software products come into existence. Such models are also marked in Table 2 to provide support for the selection of a potential quality model. Quamoco, ADEQUATE, FURPS+, GEQUAMO, [PERSON] et al. 's model, and [PERSON] et al. 's model are classified as quality models with internal, external and quality-in-use views in Table 2: the Quamoco quality model [46] encompasses an entity \"utility\" that describes the relative satisfaction of stakeholders with regard to a specific \"factor\" in the model's terminology; ADEQUATE [8; 9] determines the key personnel and their views. FURPS+ [10; 11; 12] includes systematic approaches to collect architectural requirements involving the stakeholders to consider their opinions; GEQUAMO [13] encompasses quality views for users, sponsors and developers; [PERSON] et al. 's model [2] contains usability and testability factors; [PERSON] et al. 's model [1] reflects quality characteristics for usability and human engineering, which could make it possible to consider the end user's view of quality. its novelty lies in the complex mathematical computations used in a clustering approach, although the model published demonstrated internal quality properties only without direct guidelines for extension; SQALE also contains the testability quality property that is divided into two further quality properties, Unit Testing Testability and Integration-level Testability, that are based on the results of code analysers. GQM [60] and SQUID [14] are rather general quality assessment approaches with no predefined quality models. These approaches assume the creation of a software product quality model or the use of an existing one, named content model in SQUID terminology, which is suitable to achieve the goals set in the given context. Consequently, the quality views they consider depend on the defined metrics and goals. In the published case study with the model definition [14], SQUID also encompasses metrics that can only be collected when the software is operational and metrics on usability that allow the expression of end users' quality perception. For these reasons, they are classified in Table 2 as quality assessment approaches with quality views that depend on the quality model used. In addition to the quality views applied, further information is presented in the columns: \"Predefined Quality Properties or Metrics Available\" to describe whether the specified model defines quality properties with associated computation methods; \"Research Interest\" to indicate whether there are more publications related to the quality model and one in the last five years; \"Widespread Use Cases\" to provide the judgement based on the specified model's 12-month average GRSI indicator from Table 1; \"Also Process Related Properties\" to show whether the specified model is a hybrid model with quality properties that describe process quality. From Table 2, it is clear that the identified software product quality model families apply different quality views to capture the abstract notion of quality. The capabilities of the listed software product quality models deviate significantly; many of them are unable to assess the external quality view and the quality-in-use view. The provided taxonomy makes it possible to interpret the quality assessment results. Based on quality assessments with internal quality view only, it is not possible to make valid statements regarding software product quality as a whole. This is because such models lack the capability to capture how the software behaves while it is used and how the end user perceives its quality.