Recently, as IT convergence has seen rapid growth the role and scope of software has been extended. many software companies are trying to improve the software quality and project outcome using software process improvement approach to cope with increasing software demands and software quality. Although software process improvement is difficult task which requires a lot of cost and time, there is still insufficient objective evidence on business benefits by its deployment. The purpose of this study is to analyze the relationship between software process improvement and software project productivity. That is, we investigated whether there is difference in software development productivity depends on software engineering level using statistical methods. We found that the software development productivity is different across the software engineering levels and the higher software engineering level can lead to improved software development productivity.