In this paper we identify key attributes of projects in which the number of problem reports after release is remarkable in the communication software. After several interviews to software project managers, we derived candidate attributes of importance to the projects. To find out the most influential attributes of the projects, we conducted statistical analysis using a set of metrics data related to the candidate attributes and the number of problem reports after release. As a result, we successfully found that two metrics concerning the origin's quality and the changes in specification are useful to estimate the field quality.