A Pareto chart should be used to identify the steps in the development process that are the source of the most software defects. The Pareto chart is a bar graph that identifies the most significant factors in a dataset and is based on the Pareto principle (80/20 rule), which suggests that 80% of problems are often due to 20% of the causes. This tool helps in pinpointing the primary sources of defects so that improvement efforts can be focused effectively.
References:
* Juran, J. M., & Godfrey, A. B. (1999). Juran's Quality Handbook (5th Edition).
* Montgomery, D. C. (2009). Introduction to Statistical Quality Control (6th Edition).