The authors present the concept of error life span and discuss its relationship to programmer performance. They collected data from student projects and obtained from the data, the error life spans. The results show that there is high correlation between the normalized sum of error life spans and programmer performance. The authors have also collected data from two distinct student projects. The majority of students showed similar scores in each project. Since obtaining the error life spans requires great effort, the authors have devised a practical method to automatically obtain estimated values of the error life spans.