---
title: "Session 17 — Reading RCT tables"
author: "Prof. Dae-Jin Lee (daelee@faculty.ie.edu)"
output: html_document
---

```{r setup, message=FALSE, warning=FALSE}
library(tidyverse)
exp <- read_csv("data/diplomacy_experiment.csv")
```

```{r}
m0 <- lm(
  post_support_diplomatic_cooperation ~ treatment_message,
  data = exp
)
m1 <- lm(
  post_support_diplomatic_cooperation ~ treatment_message + prior_support,
  data = exp
)

summary(m0)
summary(m1)
confint(m0)
confint(m1)
```

**Discuss:** Why can we include `prior_support` without “creating” identification? What changes in the treatment coefficient, and how would you brief both columns?