Estimating Web Service interface complexity and quality through conventional object-oriented metrics José Luis Ordiales Coscia 2 , Marco Crasso 1,2,3 , Cristian Mateos 1,2,3 , and Alejandro Zunino 1,2,3 1 ISISTAN Research Institute. {mcrasso,cmateos,azunino}@conicet.gov.ar 2 UNICEN University. jlordiales@gmail.com 3 Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Abstract. Historically, software engineers have conceived metric suites as valu- able tools to estimate the quality of their software artifacts. Recently, a fresh computing paradigm called Service-Oriented Computing (SOC) has emerged at the crossing of massively distributed and heterogeneous software. This paper presents a statistical correlation analysis showing that classic software engineer- ing metrics can be used to predict the complexity and quality of WSDL docu- ments, the cornerstone software artifact when materializing this novel comput- ing paradigm with Web-based technologies. For the experiments, 154 real world WSDL documents have been employed. Keywords: SERVICE-ORIENTED COMPUTING; WEB SERVICES; CODE- FIRST; OBJECT-ORIENTED METRICS; EARLY DETECTION. 1 Introduction The Service-Oriented Computing (SOC) paradigm has been steadily gaining territory in the software industry. With SOC, the composition of loosely coupled pieces of software, called services, drives software construction. A key to SOC is that services may be provided by third-parties who only expose services interfaces to the outer world. This basic idea has been present in the software industry since a long time ago. How- ever, the advances in distributed system technologies nowadays encourage engineers to implement the SOC paradigm in environments with higher levels of distribution and heterogeneity. For instance, broadband and ubiquitous connections enable to reach the Internet from everywhere and at every time, enabling a global scale marketplace of soft- ware services. In such a marketplace, providers may offer their services interfaces and consumers may invoke them regardless geographical aspects, using the current Web infrastructure as the communication channel. When services are implemented using standard Web languages and protocols –which is the most common scenario– they are called Web Services. Nowadays, Web Services are the leading character in diverse con- texts. For example, they are the chosen technology usually employed when migrating legacy systems [13] or the technological protocol stack used when accessing remote information from smartphones [11].