Web Framework Points: an Effort Estimation Methodology for Web Application Development

Software effort estimation is one of the most critical components of a successful software project: completing the project on time and within budget is the classic challenge for all project managers. However, predictions made by project managers about their project are often inexact: software projects need, on average, 30-40% more effort than estimated. Research on software development effort and cost estimation has been abundant and diversified since the end of the Seventies. The topic is still very much alive, as shown by the numerous works existing in the literature. During these three years of research activity, I had the opportunity to go into the knowledge and to experiment some of the main software effort estimation methodologies existing in literature. In particular, I focused my research on Web effort estimation. As stated by many authors, the existing models for classic software applications are not well suited to measure the effort of Web applications, that unfortunately are not exempt from cost and time overruns, as traditional software projects. Initially, I compared the effectiveness of Albrecht's classic Function Points (FP) and Reifer's Web Objects (WO) metrics in estimating development effort for Web applications, in the context of an Italian software company. I tested these metrics on a dataset made of 24 projects provided by the software company between 2003 and 2010. I compared the estimate data with the real effort of each project completely developed, using the MRE (Magnitude of Relative Error) method. The experimental results showed a high error in estimates when using WO metric, which proved to be more effective than the FP metric in only two occurrences. In the context of this first work, it appeared evident that effort estimation depends not only on functional size measures, but other factors had to be considered, such as model accuracy and other challenges specific to Web applications; though the former represent the input that influences most the final results. For this reason, I revised the WO methodology, creating the RWO methodology. I applied this methodology to the same dataset of projects, comparing the results to those gathered by applying the FP and WO methods. The experimental results showed that the RWO method reached effort prediction results that are comparable to – and in 4 cases even better than – the FP method. Motivated by the dominant use of Content Management Framework (CMF) in Web application development and the inadequacy of the RWO method when used with the latest Web application development tools, I finally chose to focus my research on the study of a new Web effort estimation methodology for Web applications developed with a CMF. I proposed a new methodology for effort estimation: the Web CMF Objects one. In this methodology, new key elements for analysis and planning were identified; they allow to define every important step in the development of a Web application using a CMF. Following the RWO method approach, the estimated effort of a Web project stems from the sum of all elements, each of them weighted with its own complexity. I tested the whole methodology on 9 projects provided by three different Italian software companies, comparing the value of the effort estimate to the actual, final effort of each project, in man-days. I then compared the effort estimate both with values obtained from the Web CMF Objects methodology and with those obtained from the respective effort estimation methodologies of the three companies, getting excellent results: a value of Pred(0.25) equal to 100% for the Web CMF Objects methodology. Recently, I completed the presentation and assessment of Web CMF Objects methodology, upgrading the cost model for the calculation of effort estimation. I named it again Web Framework Points methodology. I tested the updated methodology on 19 projects provided by three software companies, getting good results: a value of Pred(0.25) equal to 79%. The aim of my research is to contribute to reducing the estimation error in software development projects developed through Content Management Frameworks, with the purpose to make the Web Framework Points methodology a useful tool for software companies.