Data was obtained in R format from Erik Voeten’s dataset here (specifically, under “Raw data”).

load("undata-213.RData")
YES <- 1
ABSTAIN <- 2
NO <- 3
ABSENT <- 8
NOTAMEMBER <- 9
library(plyr)
library(dplyr)
library(tidyr)

votes <- x %>% tbl_df() %>%
    select(rcid, session, date, unres, vote, country = uniquename) %>% # just relevant columns
    mutate(country = factor(gsub('"', '', country))) %>%
    filter(vote %in% c(YES, NO, ABSTAIN)) %>%
    separate(date, c("year", "month", "day"), sep = "-", remove = FALSE) %>%
    mutate(year = as.numeric(year), month = as.numeric(month), date = as.numeric(date))

Yes votes over time

We look at the trends of the frequency of Yes votes over time.

byyear <- votes %>% group_by(country, year) %>%
    summarize(yes = mean(vote == YES), no = mean(vote == NO))

# for now, consider the UN Security Council countries
countries <- c("United States of America", "United Kingdom", "U.S.S.R.",
               "Russian Federation", "China", "France", "Taiwan")

library(ggplot2)
byyear %>% filter(country %in% countries) %>%
    ggplot(aes(year, yes, color = country)) + geom_point() +
    stat_smooth(se = FALSE) +
    ylab("% of votes that are Yes")

plot of chunk byyear

(Note that Taiwan became China, and the U.S.S.R. became the Russian Federation. Note also the wide gap that occurs at each of these transitions).

Number of votes per country is bimodal

bycountry <- votes %>% group_by(country) %>% summarize(total = n())
qplot(bycountry$total, binwidth = 500)

plot of chunk unnamed-chunk-2

This suggests we should filter out countries with fewer Yes/No votes, which will add noise to our correlation measurement.

manyvote_countries <- bycountry$country[bycountry$total > 2000]

voting blocs based on Manhattan distance of voting

library(reshape2)
votematrix <- votes %>% filter(country %in% manyvote_countries) %>%
    acast(country ~ rcid, value.var = "vote")

# in new coding, 1 = YES, 0 = ABSTAIN, -1 = NO
votematrix <- 2 - votematrix
# construct a correlation matrix
cormat <- cor(t(votematrix), method = "spearman", use = "pairwise.complete.obs")
# replace missing values with 0 (not perfect!)
cormat[is.na(cormat)] <- 0
h <- hclust(dist(votematrix, method = "manhattan"))
plot(h, cex = .6)

plot of chunk hclust