Quality and Reliability Methods - SAS

280 Degradation Chapter 16
The Degradation Report
Table 16.1 Explanation of Degradation Launch Window (Continued)
Role
X
Label, System ID
Freq
Censor
By
Application
Explanation
Assign a covariate variable.
Assign the column that designates the unit IDs.
Assign a column giving a frequency for each row.
Assign a column that designates if a unit is censored.
Assign a variable to produce an analysis for each level of the variable.
Select one of the following analysis methods:
Repeated Measures Degradation is used to perform linear or nonlinear
degradation analysis. This option does not allow for censoring. If your
data involves censoring, use the Destructive Degradation option.
Stability Test is used to perform a stability analysis for setting
pharmaceutical product expiration dates. For more information about
stability analyses, see “Stability Analysis” on page 301.
Destructive Degradation is used if units are destroyed during the
measurement process, or if you have censored data. For more
information, see “Destructive Degradation” on page 298.
Censor Code
Upper Spec Limit
Lower Spec Limit
Censoring Time
Specify the value in the Censor column that designates censoring.
Assign an upper spec limit.
Assign a lower spec limit.
Assign a censoring value.
The Degradation Report
To produce the report shown in Figure 16.3, follow the steps below using the GaAs Laser.jmp data table.
This table is from Meeker and Escobar (1998) and contains measurements of the percent increase in
operating current taken on several gallium arsenide lasers. When the percent increase reaches 10%, the laser
is considered to have failed.
1. Open the GaAs Laser.jmp data table in the Reliability folder of Sample Data.
2. Select Analyze > Reliability and Survival > Degradation.
3. Select Current and click Y, Response.
4. Select Hours and click Time.
5. Select Unit and click Label, System ID.