Quality of Open Source Software: The QualiPSo Trustworthiness Model

Trustworthiness is one of the main issues upon which the decision whether to adopt an Open-Source Software (OSS) product is based. The work described here is part of an activity that has the goals of 1) defining an adequate notion of trustworthiness of software products and artifacts and 2) identifying a number of factors that influence it. Specifically, this paper reports about the identification of the "dimensions" of trustworthiness, i.e., of the high-level qualities that software products and artefacts have to posses in order to be considered trustworthy. These dimensions are described by means of a conceptual model of trustworthiness, which comprises the representation of the factors that affect the user's perception of trustworthiness, as well as the objective characteristics of the products that contribute to "build" trustworthiness. The aforementioned model is equipped with a measurement plan that describes, at the operational level, how to perform the evaluation of the trustworthiness of OSS products. The proposed model provides the basis to build quantitative models of the trustworthiness of OSS products and artifacts that are able to explain the relationships between the (objectively observable) characteristics of OSS products and the level of trustworthiness perceived by the users of such products.