Profilers > Simulator > Defect Profiler > Defect Rates
Publication date: 08/13/2020

Defect Rates

The mean and standard deviation (SD) of the simulated overall defect rate are reported below each defect profile plot. This mean is calculated by integrating the defect profile curve with the specified factor distribution. Because of numerical error in the estimations, the overall mean defect rate reported under each factor can differ slightly.

The defect rates that are reported in the Defect Profiler are estimates of the simulated overall defect rate. This rate is also reported in the Rate column of the defect table that is in the Prediction Profiler outline.

Note: The defect table is added to the Prediction Profiler outline after you run a simulation and one or more of your responses has defined spec limits.

Because the rate estimates are obtained differently, by integration and simulation, they might differ slightly. If they are very different, you might consider increasing the number of simulation runs. In addition, verify that the range of the factor scale is wide enough so that the integration covers the distribution well.

The standard deviation is a measure of the sensitivity of the defect rate to the factor. It is small when either the factor profile is flat or the factor distribution has a small variance. The larger the standard deviation, the larger the impact that changes in that factor have on the defect rate variability. Comparing SDs across factors enables you to select factors for improvement to reduce defect rates.

The mean and SD values are updated when you change the factor distribution settings. This is one way to explore how to reduce defects as a function of one particular factor at a time. You can click and drag a handle point on the factor distribution and watch the mean and SD change as you drag. However, changes are not updated across all factors until you click the Rerun button to generate updated simulation runs.

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