Variables provide SEER*Stat with formatting information for the fields in the database. When you create a user-defined variable, you are actually defining new format information for an existing variable, and are not changing the underlying data in the database. For convenience, the dictionary distributed with a database contains one variable for each field. For example, the Year of diagnosis variable includes one grouping for all years combined (e.g.,1973-2000) and separate groupings for each individual year. When showing statistics by year of diagnosis, if years are excluded from the analysis, then you need to create a new variable based on year of diagnosis. Otherwise, the value for all years combined will be mislabeled.
In general, you need to create a variable when:
A variable of interest does not have groupings appropriate for your analysis. Create a user-defined variable using one variable as the template or base variable. The base variable can be any currently defined variable (other than merged variables).
You need a variable with groupings based on values from two or more variables. For example, if you are using the Site recode variable and would like to display small cell lung cancer vs. non-small cell lung cancer, you could create a merged variable based on Site recode and Histology.
Follow the steps listed below to create a variable in SEER*Stat. The controls for creating a new user-defined variable are the same as those used to edit an existing user-defined variable.
Open the dictionary.
Determine whether you need to create a user-defined variable (formatting using values of just one variable) or a merged variable (formatting based on values of two or more variables).
If all of the new variable's groupings can be defined based on one variable, select the base variable from the categories displayed and click Create. (Use the Find button if you are having trouble locating the desired base variable.)
If the new variable will have groupings based on the values of more than one variable, click Merge to begin creating a new merged variable. Alternatively, you may use an existing merged variable as a template. Select the template variable from the Merged folder, then click Merge.
Follow the instructions in Edit Variable Dialog or Edit Merged Variable Dialog.