---
title: "Session 13 — Country indicators caution"
author: "Prof. Dae-Jin Lee (daelee@faculty.ie.edu)"
date: "Fall 2026"
output:
  html_document:
    theme: flatly
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE, message = FALSE, warning = FALSE)
library(tidyverse)
```

```{r}
world <- read_csv("data/country_indicators.csv")
glimpse(world)

world |>
  summarise(
    mean_democracy = mean(democracy_score, na.rm = TRUE),
    mean_life_exp = mean(life_expectancy, na.rm = TRUE)
  )
```

This file is a **cross-section**, not two waves. Use it to discuss why “worst countries improved next year” claims need panel data — then return to the simulation for the actual reversion demonstration.