Table of Links Abstract and 1. Introduction Abstract and 1. Introduction Background and 2.1. Related Work 2.2. The Impact of XP Practices on Software Productivity and Quality 2.3. Bayesian Network Modelling Model Design 3.1. Model Overview 3.2. Team Velocity Model 3.3. Defected Story Points Model Model Validation 4.1. Experiments Setup 4.2. Results and Discussion Conclusions and References Background and 2.1. Related Work 2.2. The Impact of XP Practices on Software Productivity and Quality 2.3. Bayesian Network Modelling Background and 2.1. Related Work Background and 2.1. Related Work 2.2. The Impact of XP Practices on Software Productivity and Quality 2.2. The Impact of XP Practices on Software Productivity and Quality 2.3. Bayesian Network Modelling 2.3. Bayesian Network Modelling Model Design 3.1. Model Overview 3.2. Team Velocity Model 3.3. Defected Story Points Model Model Design Model Design 3.1. Model Overview 3.1. Model Overview 3.2. Team Velocity Model 3.2. Team Velocity Model 3.3. Defected Story Points Model 3.3. Defected Story Points Model Model Validation 4.1. Experiments Setup 4.2. Results and Discussion Model Validation Model Validation 4.1. Experiments Setup 4.1. Experiments Setup 4.2. Results and Discussion 4.2. Results and Discussion Conclusions and References Conclusions and References Conclusions and References 3. MODEL DESIGN The proposed model complies XP process iterative structure. The model considers the iterative nature of XP by modelling the process as a number of sequential releases. An example of releases connectivity is shown in Figure 2. Each release has eight inputs and two outputs. The output of one release is considered as an input for the following release. In the next section, the model details explaining different inputs and outputs are provided. Then, the details of the Team Velocity Model and Project Defects Model will be provides in the following sections. Authors: (1) Mohamed Abouelelam, Software System Engineering, University of Regina, Regina, Canada; (2) Luigi Benedicenti, Software System Engineering, University of Regina, Regina, Canada. Authors: Authors: (1) Mohamed Abouelelam, Software System Engineering, University of Regina, Regina, Canada; (2) Luigi Benedicenti, Software System Engineering, University of Regina, Regina, Canada. This paper is available on arxiv under CC BY-NC-ND 4.0 DEED license. This paper is available on arxiv under CC BY-NC-ND 4.0 DEED license. available on arxiv available on arxiv