Appendixes | Report Option Descriptions | Fixed Effects

Fixed Effects
Use this field to specify effects by which to model the mean of the response variable .
This option is available only when the Response Type is an incidence density.
Note : Do not specify the treatment variable as it is automatically included.
Observe the following conventions in this field:
Use an asterisk ( * ) to create interactions. For example, assuming A and B are listed as Class Variables , specifying A B A*B constructs a two-way ANOVA model.
Use a vertical bar ( | ) to create main effects and interactions. For example, A|B|C is the same as A B A*B C A*C B*C A*B*C .
Use an at-sign ( @ ) following the use of vertical bars to remove interaction terms. For example, A|B|C@2 removes the three-way interaction term from A|B|C .
To Specify Fixed Effects:
*
Make sure that either Incidence density based on first event only or Incidence density based on all events is selected as the Response Type .
*
Enter the fixed effects in the Fixed Effects field.
*
For example, to group the data from different study sites (listed in the SITEID column) into levels, type SITEID in the text box, as shown below:
*