Defining Stream Performance

Represented by the number grade (1, 2, 3), stream performance is a ratio of the stream’s expected yield (long-term sigma), which is based on the stream's actual performance, to the stream’s potential yield (short-term sigma).

For example, consider the following process with an expected yield of 85%.

To determine the stream's performance, divide the expected yield by the potential yield.

The assigned number grade is based on the result of that division, as follows:

• Number Grade 1

  

  • High performance ratio: 95%-100%
  • Production runs that are stable and little difference between runs are present (e.g. minimal shift to shift variation)

• Number Grade 2

  

  • Moderate performance ratio: 90%-95%
  • Production runs with some differences (e.g. some shift to shift variation)

• Number Grade 3

  

  • Low performance ratio: <= 90%
  • Production runs with significant differences (e.g. shift to shift variation)

To view grading categories, please see Grading Categories.