CAEFFECT Procedure

The DIFFERENCE statement specifies causal effects to estimate on the difference scale. Causal effects on the difference scale are computed by taking a potential outcome mean that is defined by an event level and subtracting a potential outcome mean that is defined by a reference level.

You can use the following options to specify the treatment levels for causal effect estimates:

The levels of treatment that you specify in the reference-list and event-list must also be used to define a potential outcome in a POM statement.

If you specify both a reference-list and a event-list, causal effects are computed for each unique pair of treatment levels between the two lists. If you specify a reference-list but not an event-list, a causal effect is computed for each treatment level in the reference-list and all other levels of treatment that you specify in a POM statement that do not appear in the reference-list. If you specify an event-list but not a reference-list, a causal effect is computed for each treatment level in the event-list and all levels of treatment that you specify in a POM statement that do not appear in the event-list. You can specify more than one DIFFERENCE statement.

If the treatment variable is a character variable, each treatment level that you specify in the reference-list and event-list should be enclosed in quotes.