In an investigating study to trace the productivity changes of a commercial software project, which uses incremental and iterative development model, we've found evidence that attributes such as staffing stability, design compatibility/ adaptability to incremental and iterative development, and integration and testing would have significant impact on modifying the productivity outcome - either positive or negative. In this report, we will present an empirical analysis to review, evaluate, and discuss these influential attributes in regard of their correlations with productivity in incremental and iterative software development. We also hope that our approach and results would contribute to initiate more research in this subject area.