---
title: "G&W and COW country code differences"
author: "Andreas Beger"
date: "`r Sys.Date()`"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{G&W and COW country code differences}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

```{r setup, include = FALSE}
knitr::opts_chunk$set(echo = FALSE)

library("states")
library("dplyr")
```

The COW and G&W state system lists generally have high overlap, but there are differences in states start and end dates, and also some differences in which numeric code is used for a particular states. Some notable code differences for post-WW2 states to look out for when trying to merge datasets with/from COW to G&W coding are:

| Case                                                | G&W          | COW          |
|-----------------------------------------------------|--------------|--------------|
|Germany after 1990 unification                       | continue 260 |          255 |
|Yemen after 1990 unification                         | continue 678 |          679 |
|Serbia after 2006 dissolution of Serbia & Montenegro | 340          | continue 345 |
|Kiribati                                             | 970          |          946 |
|Nauru                                                | 971          |          970 |
|Tuvalu                                               | 973          |          947 |
|Tonga                                                | 972          |          955 |