|This study tried to explain the performance of software projects within the OSS-community by looking at the project size and their social network characteristics. Three ways of how project size could affect project performance have been investigated: (1) the direct influence of project size on project performance, (2) the influence of project size on project performance, via social network characteristics, (3) the moderating effect of project size on the relationships between social network characteristics and project performance. Data has been gathered from the SourceForge database, which consisted of more than 30,000 projects. Classical social network theories as well as logical knowledge and mathematical models are used to formulate the hypotheses. Findings show that project size does not affect project performance directly, but rather affects project performance indirectly, going through social network characteristics. Also, project size shows to moderate the relationships between several social network characteristics and project performance.