PS_SAM_data: Simulated Data for the Construction of Propensity...

In SAMprior: Self-Adapting Mixture (SAM) Priors

Simulated Data for the Construction of Propensity Score-Integrated Informative Priors

Description

This dataset demonstrates the construction of a Propensity Score-Integrated (PS) SAM prior. It simulates a two-arm randomized clinical trial (RCT) with a 2:1 randomization ratio between treatment and control arms, considering both binary and continuous endpoints.

Usage

PS_SAM_data

Format

A data frame with 600 observations.

• "A" is the treatment assignment (1 = treated, 0 = control).

• "G" is the study indicator (1 = current, 0 = historical).

• "X_1" is a binary covariate.

• "X_2" is a continuous covariate.

• "X_3" is a continuous covariate.

• "Y_{binary}" is binary outcome.

• "Y_{continuous}" is continuous outcome.

Details

The dataset includes:

• Sample size for treatment arm: n_t = 200.

• Sample size for control arm: n_c = 100.

• Sample size for historical control study: n_h = 300.

Covariates for the control arm were generated from

X_1 \sim Ber(0.5), ~~ X_2 \sim N(0, 1), ~~ X_3 \sim N(0.5, 1),

where Ber(\cdot) stands for Bernoulli distribution. Covariates for the historical controls were generated from a mixture distribution, with half were generated the same as for the control arm, while the other half were drawn from

X_1 \sim Ber(0.8), ~~ X_2 \sim N(-0.4, 1), ~~ X_3 \sim N(-0.2, 1).

For the binary endpoint, y_i were generated from the logit model:

logit(\Pr(y_i = 1 | X_{1i}, X_{2i}, X_{3i}, A_i)) = -1.4 - 0.5 X_{1i} + X_{2i} + 2 X_{3i} + \lambda A_i,

where \lambda is the treatment effect size, and we let \lambda = 0.9 to generate a moderate treatment effect size so that they study has a reasonable power.

For the continuous endpoint, y_i were generated from the following normal model:

y_i = 1.8 X_{1i} + 0.9 X_{2i} - 2 X_{3i} + \lambda A_i + \epsilon_i,

where we let \lambda = 1, and \epsilon_i \sim N(0, 3.5^2).

This dataset enables evaluation of the PS-SAM prior's performance in addressing heterogeneity between the RCT control arm and historical controls.

Examples

# Load the dataset
data(PS_SAM_data)

# View the structure
str(PS_SAM_data)

SAMprior documentation built on April 4, 2025, 2:29 a.m.