CSSM Procedure

What-If Analysis and Process Control

Suppose that a score-store, such as mylib.inscore, contains context information based on the data up to time T (bold upper D Subscript 1 colon upper T), and suppose you are interested in predicting and/or interpolating the response sequence for the next p time points. You can easily accomplish this in PROC CSSM by using a suitable data packet bold upper D Subscript left-parenthesis upper T plus 1 right-parenthesis colon left-parenthesis upper T plus p right-parenthesis (or bold upper D Subscript upper T colon left-parenthesis upper T plus p right-parenthesis when multiple observations can share the same time index) as the input data table and by using mylib.inscore as the input score store in the SCORE statement (score in=mylib.inscore;). This is called the scoring of data in bold upper D Subscript left-parenthesis upper T plus 1 right-parenthesis colon left-parenthesis upper T plus p right-parenthesis. Because the missing values in the response variables are an indication to PROC CSSM to compute model-based predictions/interpolations, you must set the values of bold upper Y to missing in appropriate rows of bold upper D Subscript left-parenthesis upper T plus 1 right-parenthesis colon left-parenthesis upper T plus p right-parenthesis (of course, you must provide appropriate nonmissing values for the predictor variables bold upper X and bold upper W).

In what-if analysis, you are interested in predicting the future course of response values for different settings of the predictors bold upper X and bold upper W. You can achieve this by repeatedly scoring bold upper D Subscript left-parenthesis upper T plus 1 right-parenthesis colon left-parenthesis upper T plus p right-parenthesis for different settings of bold upper X and bold upper W, while keeping the input score-store the same. See Example 14.19: Scenario Analysis Using Scoring for an illustration of this type of what-if analysis.

In process control, the goal is to find suitable predictor settings so that the future response values are close to some desirable levels. In an informal, quick-and-dirty approach, you can do this by repeatedly scoring bold upper D Subscript left-parenthesis upper T plus 1 right-parenthesis colon left-parenthesis upper T plus p right-parenthesis with different trial values of predictors. In a formal approach, you can use the scoring functionality to define a suitable objective function, which you can optimize by using sophisticated optimization methods to find the optimal predictor settings.

Last updated: July 09, 2026