I'm trying to get my head around the mediation package in R, using the vignette for the package.
I'm struggling to understand the output of the mediate()
function.
require("mediation")
require("sandwich")
data("framing")
med.fit <- lm(emo ~ treat + age + educ + gender + income, data = framing)
out.fit <- glm(cong_mesg ~ emo + treat + age + educ + gender + income,
data = framing, family = binomial("probit"))
summary(out.fit)
# OR for sending a message to a senator for treated compared to untreated.
exp(as.numeric(coef(out.fit)[3]))
# mediation
med.out <- mediate(med.fit, out.fit, treat = "treat", mediator = "emo",
robustSE = TRUE, sims = 100)
summary(med.out)
...
Estimate 95% CI Lower 95% CI Upper p-value
ACME (control) 0.0802 0.0335 0.1300 0.00
ACME (treated) 0.0808 0.0365 0.1311 0.00
ADE (control) 0.0142 -0.1030 0.1325 0.78
ADE (treated) 0.0147 -0.1137 0.1403 0.78
Total Effect 0.0949 -0.0316 0.2129 0.14
Prop. Mediated (control) 0.7621 -2.0926 4.9490 0.14
Prop. Mediated (treated) 0.7842 -1.9272 4.6916 0.14
ACME (average) 0.0805 0.0350 0.1304 0.00
ADE (average) 0.0145 -0.1087 0.1364 0.78
Prop. Mediated (average) 0.7731 -2.0099 4.8203 0.14
...
Does this mean that 8.08 % of the effect of treatment is mediated through emotional state, among those that are treated? Or is this a change in the coefficient of treat
?
If someone could explain the output it would be much appreciated.