Integration Point: Response - Time-to-Event Outcome
Gabriel Potvin
January 09, 2026
IntegrationPointResponseTimeToEvent.RmdGo back to the Integration Point: Response page
Important: ArrivalTime is a new required parameter. Existing R scripts must be updated to include this parameter in the function definition, even if it is not used.
Input Variables
When creating a custom R script, you can optionally use specific
variables provided by East Horizon’s engine itself. These variables are
automatically available and do not need to be set by the user, except
for the UserParam variable. Refer to the table below for
the variables that are available for this integration point and
outcome.
| Variable | Type | Description |
|---|---|---|
| NumSub | Integer | Number of subjects in the trial. |
| NumArm | Integer | Number of arms in the trial ﴾including placebo/control, and experimental﴿. |
| ArrivalTime | Vector of Numeric | Vector of length NumSub, indicating the arrival time
for each subject. |
| TreatmentID | Vector of Integer | Vector of length NumSub, indicating the allocation of
subjects to arms. Index 0 represents placebo/control. For
example, [0, 0, 1] indicates three subjects: two in the
control group and one experimental. |
| StratumID | Vector of Integer | Vector of length NumSub, indicating the stratum index
to which each subject is allocated. Only required when
Stratification is turned on. |
| SurvMethod | Integer | Selected input method for survival analysis from the East Horizon
dropdown list: – 1: Hazard rate.– 2:
Cumulative % survival rates.– 3: Median survival
times. |
| NumPrd | Integer | Number of periods in the trial. Fixed to 1 for
Study Objective = Multiple Arm Confirmatory and when
Stratification is turned on. |
| PrdTime | Matrix of Numeric | 2D array of size NumPrd x NumArm, indicating the times
used to specify survival parameters. If Stratification is
turned on, the size is Number of Strata x NumArm. Equals to
NA for the control arm. Depends on SurvMethod:– If SurvMethod = 1: Starting time of hazard pieces for each
period or factor.– If SurvMethod = 2: Time at which the
cumulative % survival is specified for each period or factor.– If SurvMethod = 3: Defaults to 0. |
| SurvParam | Matrix of List | 2D array of size NumPrd x NumArm, indicating the
survival parameters. If Stratification is turned on, the
size is Number of Strata x NumArm. Depends on
SurvMethod:– If SurvMethod = 1: Specifies
hazard rates per arm per period or stratum. SurvParam[i, j]
represents the hazard rate for the jth arm in the
ith period or factor– If SurvMethod = 2:
Specifies cumulative % survival rates per arm per period or factor.
SurvParam[i, j] represents the cumulative % survival for
the jth arm in the ith period or factor.– If SurvMethod = 3: Contains median survival times for each
arm (per stratum if using Stratification). Only one row if
not using Stratification. SurvMethod[i, j]
represents the median survival time for the jth arm (in the
ith factor, if using Stratification). |
| UserParam | List | Contains all user-defined parameters specified in the East Horizon
interface (refer to the Instructions
section). To access these parameters in your R code, use the syntax:
UserParam$NameOfTheVariable, replacing
NameOfTheVariable with the appropriate parameter name. |
Expected Output Variable
East Horizon expects an output of a specific type. Refer to the table below for the expected output for this integration point:
| Type | Description |
|---|---|
| List | A named list containing SurvivalTime and
ErrorCode. |
Expected Members of the Output List
| Members | Type | Description |
|---|---|---|
| SurvivalTime | Vector of Numeric | Vector of length NumSub, containing the generated time
to response values for each subject. |
| ErrorCode | Integer | Optional. Can be used to handle errors in your script: – 0: No error.– Positive Integer: Nonfatal
error, the current simulation will be aborted, but the next simulation
will proceed.– Negative Integer: Fatal error, no
further simulations will be attempted. |
Note: Additional custom variables can be included as members of the
output list. All outputs will automatically be available as input
variables for analysis or treatment selection endpoints in the
SimData variable as described here: Variables of SimData.
Minimal Template
Your R script could contain a function such as this one, with a name
of your choice. All input variables must be declared, even if they are
not used in the script. We recommend always declaring
UserParam as a default NULL value in the
function arguments, as this will ensure that the same function will work
regardless of whether the user has specified any custom parameters in
East Horizon.
Detailed templates with step-by-step explanations are available here: SimulatePatientOutcome.TimeToEvent.R and SimulatePatientOutcome.TimeToEvent.Stratification.R for Stratification.
GenerateResponse <- function( NumSub, NumArm, ArrivalTime, TreatmentID, SurvMethod, NumPrd, PrdTime, SurvParam, UserParam = NULL )
{
nError <- 0 # Error handling (no error)
vSurvTime <- rep( 0, NumSub ) # Initializing survival times array to 0
# Write the actual code here.
# Store the generated survival time values in a vector called vSurvTime.
return( list( SurvivalTime = as.double( vSurvTime ), ErrorCode = as.integer( nError ) ) )
}For Stratification turned on
GenerateResponse <- function( NumSub, NumArm, ArrivalTime, TreatmentID, StratumID, SurvMethod, NumPrd, PrdTime, SurvParam, UserParam = NULL )
{
nError <- 0 # Error handling (no error)
vSurvTime <- rep( 0, NumSub ) # Initializing survival times array to 0
# Write the actual code here.
# Store the generated survival time values in a vector called vSurvTime.
return( list( SurvivalTime = as.double( vSurvTime ), ErrorCode = as.integer( nError ) ) )
}