Table 2.
"Statements" and their components in the stratify macro.
| statement or statement component | Comment |
| ZRTF varname | varname must be a valid SAS variable name. |
| l(en(gth)) = | the length of varname. By default, 8 for numeric variables and the maximum length of VALUEC in EXPDATS for character variables. |
| c(ond(ition)) = | the value of the character variable EXPEVENT that will trigger the (re-)evaluation of varname. There are restrictions on the value of this variable to avoid it interfering with the macro, but a valid SAS variable name will always work. It must be enclosed in "". |
| n = | the occurrence of the condition that will trigger the (re-)evaluation of varname. Possible values are f, first, l, last, or any integer > 0, where 1 means first, 2 second etc. Last is the default. |
| v(al(ue)) = | the value of varname before grouping. Possible values are: v (value at occurrence of condition = and n=) s (sum of values at occurrence of condition=) i (indicator that condition = and n = has occurred) n (number of occurrences of condition=) cv (valuec at occurrence of condition = and n=) t (time at occurrence of condition = and n=) a (age at occurrence of condition = and n=). |
| g(roups) = | for a numeric variable, the specification is X to Y by Z or X Y Z W .... or a format. For a character variable, it is a format. No grouping occurs unless specified. |
| m(iss(ing))= | value of varname when missing. If varname is a character variable, it must be enclosed in "" and the same restrictions as for condition apply. |
| BRTF varname | varname must be a valid SAS variable name. |
| t(ime) = | variable containing the time point at which speed and value are evaluated. |
| s(peed) = | variable containing the rate of change (0 or 1) of the underlying bit-rate time factor (from time and onwards). |
| v(al(ue)) = | variable containing the (ungrouped) value of varname at time. |
| c(uts) = | X to Y by Z or X Y Z W .... |
| AXIS varname | varname must be a valid SAS variable name. |
| o(ri(gin)) = | variable or constant containing the origin of the time scale |
| c(uts) = | X to Y by Z or X Y Z W .... |
| s(peed) = | variable or constant containing the rate of change. The rate of change is always 1 unless this variable or constant is set to 0. |
| EXPDATS | exposure data sets. |
| EVENTID | extra variables to include in EVENTDAT. |
| CLASS | stratifying variables to appear in OUT retained from DATA. |