ci_mediation_data: Confidence Interval for MediationData Objects

In RMediation: Mediation Analysis Confidence Intervals

Confidence Interval for MediationData Objects

Description

Computes confidence intervals for the indirect effect from a medfit MediationData object using RMediation's methods (DOP, Monte Carlo, etc.).

Usage

ci_mediation_data(mu, level = 0.95, type = "dop", n.mc = 1e+05, ...)

ci_serial_mediation_data(mu, level = 0.95, type = "MC", n.mc = 1e+05, ...)

Arguments

mu	A MediationData object from the medfit package
level	Confidence level (default 0.95 for 95% CI)
type	Type of CI method: "dop" (Distribution of Product), "MC" (Monte Carlo), or "asymp" (asymptotic normal)
n.mc	Number of Monte Carlo samples (for type = "MC")
...	Additional arguments passed to underlying methods

Details

This method extracts the a and b path coefficients from the MediationData object, along with their standard errors and covariance, and computes confidence intervals using RMediation's methods.

Method Options

• "dop": Distribution of Product method. Uses the exact or approximate distribution of the product of two normal random variables. Recommended for most applications.

• "MC": Monte Carlo simulation. Samples from the joint distribution of a and b to estimate the CI. Use n.mc to control precision.

• "asymp": Asymptotic normal approximation using the delta method. Fast but may be inaccurate for small samples or non-normal distributions.

Value

A list with components:

CI	The confidence interval (lower, upper)
Estimate	Point estimate of indirect effect (a*b)
SE	Standard error of indirect effect
type	Method used for CI computation

See Also

ci for the generic function, MediationData for the input class, ProductNormal for the underlying distribution class

Examples

## Not run: 
library(medfit)
library(RMediation)

# Fit mediation models
fit_m <- lm(M ~ X + C, data = mydata)
fit_y <- lm(Y ~ X + M + C, data = mydata)

# Extract mediation structure
med_data <- extract_mediation(fit_m, model_y = fit_y,
                               treatment = "X", mediator = "M")

# Compute CI using Distribution of Product
ci(med_data, type = "dop")

# Compute CI using Monte Carlo
ci(med_data, type = "MC", n.mc = 10000)

## End(Not run)

RMediation documentation built on June 20, 2026, 9:08 a.m.