Find definitions and interpretation guidance for every expected overall performance measure that is provided with nonnormal capability analysis.

PPM < LSL for expected overall performance is the expected number of parts per million that have measurements that are less than the lower specification limit (LSL). PPM < LSL for expected overall performance is 1,000,000 times the probability that the measurement of a randomly selected part from the selected nonnormal distribution is less than LSL.
The probability that a randomly selected part is less than LSL is shown by the shaded region under the distribution curve.

Use PPM < LSL for expected overall performance to estimate the number of nonconforming items, represented in parts per million, that you can expect to be below the lower specification limit based on the overall variation of your process. Overall performance values indicate the actual process performance that your customer experiences over time.

Lower values of PPM < LSL indicate greater process capability, relative to the lower specification limit. Ideally, few or no parts have measurements that are less than the lower specification limit.

PPM > USL for expected overall performance is the expected number of parts per million that have measurements that are greater than the upper specification limit (USL). PPM > USL for expected overall performance is 1,000,000 times the probability that the measurement of a randomly selected part from the selected nonnormal distribution is greater than USL.
The probability that a randomly selected part is greater than USL is shown by the shaded region under the distribution curve.

Use PPM > USL for expected overall performance to estimate the number of nonconforming items, represented in parts per million, that you can expect to be above the upper specification limit based on the overall variation of your process. Overall performance values indicate the actual process performance that your customer experiences over time.

Lower values of PPM > USL indicate greater process capability, relative to the upper specification limit. Ideally, few or no parts have measurements that are greater than the upper specification limit.

PPM Total for expected overall performance is the expected number of parts per million that have measurements that are outside the specification limits. PPM Total for expected overall performance is 1,000,000 times the probability that the measurement of a randomly selected part from the selected nonnormal distribution is outside the specification limits.
The probability that a randomly selected part is outside of the specification limits is shown by the shaded regions under the distribution curve.

Use PPM Total for expected overall performance to estimate the number of nonconforming items, represented in parts per million, that you can expect to be outside the specification limits based on the overall variation of your process. Overall performance values indicate the actual process performance that your customer experiences over time.

Lower values of PPM Total indicate greater process capability. Ideally, few or no parts have measurements that are outside the specification limits.

You can also use PPM to estimate the percentage of conforming and nonconforming parts in your process.

PPM | % Nonconforming Parts | % Conforming |
---|---|---|

66807 | 6.807% | 93.193% |

6210 | 0.621% | 99.379% |

233 | 0.0233% | 99.9767% |

3.4 | 0.00034% | 99.99966% |

% < LSL for expected overall performance is the expected percentage of parts that have measurements that are less than the lower specification limit (LSL). % < LSL for expected overall performance is the probability that the measurement of a randomly selected part from the selected nonnormal distribution is less than LSL. The probability that a randomly selected part is less than LSL is shown by the shaded region under the distribution curve.

Use % < LSL for expected overall performance to estimate the percentage of nonconforming items that you can expect to be below the lower specification limit based on the overall variation of your process. Overall performance values indicate the actual process performance that your customer experiences over time.

Lower values of % < LSL indicate greater process capability, relative to the lower specification limit. Ideally, few or no parts have measurements that are less than the lower specification limit.

% > USL for expected overall performance is the expected percentage of parts that have measurements that are greater than the upper specification limit (USL). % > USL expected within performance is the probability that the measurement of a randomly selected part from the selected nonnormal distribution is greater than USL.
The probability that a randomly selected part is greater than USL is shown by the shaded region under the distribution curve.

Use % > USL for expected overall performance to estimate the percentage of nonconforming items that you can expect to be above the upper specification limit based on the overall variation of your process. Overall performance values indicate the actual process performance that your customer experiences over time.

Lower values of % > USL indicate greater process capability, relative to the upper specification limit. Ideally, few or no parts have measurements that are greater the upper specification limit.

% Total for expected overall performance is the expected percentage of parts that have measurements that are outside the specification limits. % Total expected overall performance is the probability that the measurement of a randomly selected part from the selected nonnormal distribution is outside the specification limits.
The probability that a randomly selected part is outside of the specification limits is shown by the shaded regions under the distribution curve.

Use % Total for expected overall performance to estimate the percentage of nonconforming items that you can expect to be outside the specification limits based on the overall variation of your process. Overall performance values indicate the actual process performance that your customer experiences over time.

Lower values of % Total indicate greater process capability. Ideally, few or no parts have measurements that are outside the specification limits.