# Specify pre-computed variable of time at risk in patient days

Use this selection to pick a variable from DM or ADSL that represents each patients time at risk in PATIENT DAYS.

It is very important that the specified variables are in patient days only or else the calculations to patient years will not be correct. The time period of this duration for each patient should match with the flag in the AE domain that should represent whether an event started/occurred in that duration calculation for a given patient.

Note: This option is available only when Specified Patient Time at Risk and Event Flag Variables has been specified using the Determine Time at Risk and Adverse Event inclusion from: option.

### To Specify the Pre-Computed Variable:

| 8 | Make sure that Specified Patient Time at Risk and Event Flag Variables has been specified using the Determine Time at Risk and Adverse Event inclusion from: option.

| 8 | Click to open the Add window, illustrating all of the study variables, shown below:

| 8 | Select one or more variables and click to add the variables to the text field.