This paper examines the successful application of tolerances on process metrics used in management activities of an ongoing test project. Statistical process control (SPC) is not new to environments such as a factory production line, but use of SPC and tolerances in software engineering is not well established.

We report the use of tolerance bands about a process plan and associated measurement. The paper presents the implementation with some samples from our actual project. The application of tolerances has worked for us in controlling processes. We experienced a "smoother road" through the use of tolerances during schedule rush during the end of efforts. Our team has been comfortable with the technique since they allow metrics with flexibility. The processes were managed and the system could handle some variation.The result was a more stable system during the "crunch" at the end of the test cycle.

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