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Integration Point: Response - Continuous Outcome

Gabriel Potvin

October 16, 2025

IntegrationPointResponseContinuous.Rmd

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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.
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.
NumArms Integer Number of arms in the trials (includes the control arm). Only applicable when Study Objective = Multiple Arm Confirmatory.
Mean Vector of Numeric Vector of length equal to the number of arms, indicating the mean of the treatments.
StdDev Vector of Numeric Vector of length equal to the number of arms, indicating the standard deviation of the treatments.
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 Response and ErrorCode.

Expected Members of the Output List

Members Type Description
Response Vector of Double Vector of length NumSub, containing the generated responses for all subjects.
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 applicable input variables must be declared, even if they are not used in the script. Input variables that are not applicable (depending on the study objective) must not be declared. 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.Continuous.R for 2-Arm and SimulatePatientOutcome.Continuous.MAMS.R for Multiple Arm.

For Study Objective = Two Arm Confirmatory 

GenerateResponse <- function( NumSub, TreatmentID, Mean, StdDev, UserParam = NULL )
{
  nError            <- 0 # Error handling (no error)
  vPatientOutcome   <- rep( 0, NumSub ) # Initializing response array to 0  
  
  # Write the actual code here.
  # Store the generated continuous response values in a vector called vPatientOutcome.

  return( list( Response = as.double( vPatientOutcome ), ErrorCode = as.integer( nError ) ) )
}

For Study Objective = Multiple Arm Confirmatory 

GenerateResponse <- function( NumSub, NumArms, TreatmentID, Mean, StdDev, UserParam = NULL )
{
  nError            <- 0 # Error handling (no error)
  vPatientOutcome   <- rep( 0, NumSub ) # Initializing response array to 0  
  
  # Write the actual code here.
  # Store the generated continuous response values in a vector called vPatientOutcome.

  return( list( Response = as.double( vPatientOutcome ), ErrorCode = as.integer( nError ) ) )
}

Examples

Explore the following examples for more context:

  1. 2-Arm, Continuous Outcome - Patient Simulation
  2. Childhood Anxiety Trial
  3. Multiple Arm, Continuous Outcome - Patient Simulation