Convert event-level data to panel-level data with tidyr in R

Packages we will need:

library(tidyverse)
library(magrittr)
library(lubridate)
library(tidyr)
library(rvest)
library(janitor)

In this post, we are going to scrape NATO accession data from Wikipedia and turn it into panel data. This means turning a list of every NATO country and their accession date into a time-series, cross-sectional dataset with information about whether or not a country is a member of NATO in any given year.

This is helpful for political science analysis because simply a dummy variable indicating whether or not a country is in NATO would lose information about the date they joined. The UK joined NATO in 1948 but North Macedonia only joined in 2020. A simple binary variable would not tell us this if we added it to our panel data.

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We will first scrape a table from the Wikipedia page on NATO member states with a few functions form the rvest pacakage.

Click here to read more about the rvest package:

nato_members <- read_html("https://en.wikipedia.org/wiki/Member_states_of_NATO")

nato_tables <- nato_members %>% html_table(header = TRUE, fill = TRUE)

nato_member_joined <- nato_tables[[1]]

We have information about each country and the date they joined. In total there are 30 rows, one for each member of NATO.

Next we are going to clean up the data, remove the numbers in the [square brackets], and select the columns that we want.

A very handy function from the janitor package cleans the variable names. They are lower_case_with_underscores rather than how they are on Wikipedia.

Next we remove the square brackets and their contents with sub("\\[.*", "", insert_variable_name)

And the accession date variable is a bit tricky because we want to convert it to date format, extract the year and convert back to an integer.

nato_member_joined %<>% 
  clean_names() %>% 
  select(country = member_state, 
         accession = accession_3) %>% 
  mutate(member_2020 = 2020,
         country = sub("\\[.*", "", country),
         accession = sub("\\[.*", "", accession),
         accession = parse_date_time(accession, "dmy"),
         accession = format(as.Date(accession, format = "%d/%m/%Y"),"%Y"),
         accession = as.numeric(as.character(accession)))

When we have our clean data, we will pivot the data to longer form. This will create one event column that has a value of accession or member in 2020.

This gives us the start and end year of our time variable for each country.

nato_member_joined %<>% 
  pivot_longer(!country, names_to = "event", values_to = "year") 

Our dataset now has 60 observations. We see Albania joined in 2009 and is still a member in 2020, for example.

Next we will use the complete() function from the tidyr package to fill all the dates in between 1948 until 2020 in the dataset. This will increase our dataset to 2,160 observations and a row for each country each year.

Nect we will group the dataset by country and fill the nato_member status variable down until the most recent year.

nato_member_joined %<>% 
  mutate(year = as.Date(as.character(year), format = "%Y")) %>% 
  mutate(year = ymd(year)) %>% 
  complete(country, year = seq.Date(min(year), max(year), by = "year")) %>% 
  mutate(nato_member = ifelse(event == "accession", 1, 
                              ifelse(event == "member_2020", 1, 0))) %>% 
  group_by(country) %>% 
  fill(nato_member, .direction = "down") %>%
  ungroup()

Last, we will use the ifelse() function to mutate the event variable into one of three categories: 'accession‘, 'member‘ or ‘not member’.

nato_member_joined %>%
  mutate(nato_member = replace_na(nato_member, 0),
         year = parse_number(as.character(year)),
         event = ifelse(nato_member == 0, "not member", event),
         event = ifelse(nato_member == 1 & is.na(event), "member", event),
         event = ifelse(event == "member_2020", "member", event))  %>% 
  distinct(country, year, .keep_all = TRUE) -> nato_panel
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Comparing proportions across time with ggstream in R

Packages we need:

library(tidyverse)
library(ggstream)
library(magrittr)
library(bbplot)
library(janitor)

We can look at proportions of energy sources across 10 years in Ireland. Data source comes from: https://www.seai.ie/data-and-insights/seai-statistics/monthly-energy-data/electricity/

Before we graph the energy sources, we can tidy up the variable names with the janitor package. We next select column 2 to 12 which looks at the sources for electricity generation. Other rows are aggregates and not the energy-related categories we want to look at.

Next we pivot the dataset longer to make it more suitable for graphing.

We can extract the last two digits from the month dataset to add the year variable.

elec %<>% 
  janitor::clean_names()

elec[2:12,] -> elec

el <- elec %>% 
  pivot_longer(!electricity_generation_g_wh, 
               names_to = "month", values_to = "value") %>% 

substrRight <- function(x, n){
  substr(x, nchar(x) - n + 1, nchar(x))}

el$year <- substrRight(el$month, 2)

el %<>% select(year, month, elec_type = electricity_generation_g_wh, elec_value = value) 

First we can use the geom_stream from the ggstream package. There are three types of plots: mirror, ridge and proportion.

First we will plot the proportion graph.

Select the different types of energy we want to compare, we can take the annual values, rather than monthly with the tried and trusted group_by() and summarise().

Optionally, we can add the bbc_style() theme for the plot and different hex colors with scale_fill_manual() and feed a vector of hex values into the values argument.

el %>% 
  filter(elec_type == "Oil" | 
           elec_type == "Coal" |
           elec_type == "Peat" | 
           elec_type == "Hydro" |
           elec_type == "Wind" |
           elec_type == "Natural Gas") %>% 
  group_by(year, elec_type) %>%
  summarise(annual_value = sum(elec_value, na.rm = TRUE)) %>% 
  ggplot(aes(x = year, 
             y = annual_value,
             group = elec_type,
             fill = elec_type)) +
  ggstream::geom_stream(type = "proportion") + 
  bbplot::bbc_style() +
  labs(title = "Comparing energy proportions in Ireland") +
  scale_fill_manual(values = c("#f94144",
                               "#277da1",
                               "#f9c74f",
                               "#f9844a",
                               "#90be6d",
                               "#577590"))

With ggstream::geom_stream(type = "mirror")

With ggstream::geom_stream(type = "ridge")

Without the ggstream package, we can recreate the proportion graph with slightly different looks

https://giphy.com/gifs/filmeditor-clueless-movie-l0ErMA0xAS1Urd4e4

el %>% 
  filter(elec_type == "Oil" | 
           elec_type == "Coal" |
           elec_type == "Peat" | 
           elec_type == "Hydro" |
           elec_type == "Wind" |
           elec_type == "Natural Gas") %>% 
  group_by(year, elec_type) %>%
  summarise(annual_value = sum(elec_value, na.rm = TRUE)) %>% 
  ggplot(aes(x = year, 
             y = annual_value,
             group = elec_type,
             fill = elec_type)) +
  geom_area(alpha=0.8 , size=1.5, colour="white") +
  bbplot::bbc_style() +
  labs(title = "Comparing energy proportions in Ireland") +
  theme(legend.key.size = unit(2, "cm")) + 
  scale_fill_manual(values = c("#f94144",
                               "#277da1",
                               "#f9c74f",
                               "#f9844a",
                               "#90be6d",
                               "#577590"))

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Building a dataset for political science analysis in R, PART 2

Packages we will need

library(tidyverse)
library(peacesciencer)
library(countrycode)
library(bbplot)

The main workhorse of this blog is the peacesciencer package by Stephen Miller!

The package will create both dyad datasets and state datasets with all sovereign countries.

Thank you Mr Miller!

There are heaps of options and variables to add.

Go to the page to read about them all in detail.

Here is a short list from the package description of all the key variables that can be quickly added:

We create the dyad dataset with the create_dyadyears() function. A dyad-year dataset focuses on information about the relationship between two countries (such as whether the two countries are at war, how much they trade together, whether they are geographically contiguous et cetera).

In the literature, the study of interstate conflict has adopted a heavy focus on dyads as a unit of analysis.

Alternatively, if we want just state-year data like in the previous blog post, we use the function create_stateyears()

We can add the variables with type D to the create_dyadyears() function and we can add the variables with type S to the create_stateyears() !

Focusing on the create_dyadyears() function, the arguments we can include are directed and mry.

The directed argument indicates whether we want directed or non-directed dyad relationship.

In a directed analysis, data include two observations (i.e. two rows) per dyad per year (such as one for USA – Russia and another row for Russia – USA), but in a nondirected analysis, we include only one observation (one row) per dyad per year.

The mry argument indicates whether they want to extend the data to the most recently concluded calendar year – i.e. 2020 – or not (i.e. until the data was last available).

dyad_df <- create_dyadyears(directed = FALSE, mry = TRUE) %>%
  add_atop_alliance() %>%  
  add_nmc() %>%
  add_cow_trade() %>% 
  add_creg_fractionalization() 

I added dyadic variables for the

You can follow these links to check out the codebooks if you want more information about descriptions about each variable and how the data were collected!

The code comes with the COW code but I like adding the actual names also!

dyad_df$country_1 <- countrycode(dyad_df$ccode1, "cown", "country.name")

With this dataframe, we can plot the CINC data of the top three superpowers, just looking at any variable that has a 1 at the end and only looking at the corresponding country_1!

According to our pals over at le Wikipedia, the Composite Index of National Capability (CINC) is a statistical measure of national power created by J. David Singer for the Correlates of War project in 1963. It uses an average of percentages of world totals in six different components (such as coal consumption, military expenditure and population). The components represent demographic, economic, and military strength

First, let’s choose some nice hex colors

pal <- c("China" = "#DE2910",
         "United States" = "#3C3B6E", 
         "Russia" = "#FFD900")

And then create the plot

dyad_df %>% 
 filter(country_1 == "Russia" | 
          country_1 == "United States" | 
          country_1 == "China") %>% 
  ggplot(aes(x = year, y = cinc1, group = as.factor(country_1))) +
  geom_line(aes(color = country_1)) +
  geom_line(aes(color = country_1), size = 2, alpha = 0.8) + 
  scale_color_manual(values =  pal) +
  bbplot::bbc_style()

In PART 3, we will merge together our data with our variables from PART 1, look at some descriptive statistics and run some panel data regression analysis with our different variables!

Improve your visualizations with ggsave in R

When we save our plots and graphs in R, we can use the ggsave() function and specify the type, size and look of the file.

We are going to look two features in particular: anti-aliasing lines with the Cairo package and creating transparent backgrounds.

Make your graph background transparent

First, let’s create a pie chart with a transparent background. The pie chart will show which party has held the top spot in Irish politics for the longest.

After we prepare and clean our data of Irish Taoisigh start and end dates in office and create a doughnut chart (see bottom of blog for doughnut graph code), we save it to our working directory with ggsave().

To see where we set that to, we can use getwd().

ggsave(pie_chart, filename = 'pie_chart.png', width = 50, height = 50, units = 'cm')

If we want to add our doughnut chart to a power point but we don’t want it to be a white background, we can ask ggsave to save the chart as transparent and then we can add it to our powerpoint or report!

To do this, we specify bg argument to "transparent"

ggsave(pie_chart, filename = 'pie_chart_transparent.png', bg = "transparent", width = 50, height = 50, units = 'cm')

This final picture was made in canva.com

Hex color values come from coolors.co

Remove aliasing lines

Aliasing lines are jagged and pixelated.

When we save our graph in R with ggsave(), we can specify in the type argument that we want type = cairo.

I make a quick graph that looks at the trends in migration and GDP from 1960s to 2018 in Ireland. I made the lines extra large to demonstrate the difference between aliased and anti-aliased lines in the graphs.

library(Cairo)
ggsave(mig_trend, file="mig_alias.png", width = 80, height = 50, units = "cm")
ggsave(mig_trend, file="mig_antialias.png", type="cairo-png", dpi = 300,
 width = 80, height = 50, units = "cm")

When we zoom in, we can see the difference due to the anti-aliasing.

First, picture 1 appears far more jagged when we zoom in :

Figure 1: Aliased lines

And after we add Cairo package adjustment, we can see the lines are smoother in figure 2

Figure 2: Anti-aliasing lines

Doughnut graph code:

terms$duration <- as.Date(terms$end) - as.Date(terms$start)
terms$duration_number <- as.numeric(terms$duration)

terms %>%
  group_by(party) %>% 
  dplyr::summarise(max_count = cumsum(duration_number)) %>%  
  slice(which.max(max_count)) %>% 
  select(party, max_count) %>% 
  arrange(desc(max_count))

counts <- data.frame(party = c("Cumann na nGaedheal", "Fine Gael" ,"Fianna Fáil"), 
                     value = c(3381, 10143, 22539))

data <- counts %>% 
  arrange(desc(party)) %>%
  dplyr::mutate(proportion = value / sum(counts$value)*100) %>%
  dplyr::mutate(ypos = cumsum(prop)- 0.35*proportion)

data$duration <- as.factor(data$value)
data$party_factor <- as.factor(data$party)


pie_chart <- ggplot(data, aes(x = 2, y = proportion, fill = party)) +
  geom_bar(stat = "identity", width = 1, color = "white") +
  coord_polar("y", start = 0) +
  xlim(0.5, 2.5) +
  theme(legend.position="none") +
  geom_text(aes(y = ypos-1, label = duration), color = "white", size = 10) +
  scale_fill_manual(values = c("Fine Gael" = "#004266", "Fianna Fáil" = "#FCB322", "Cumann na nGaedheal" = "#D62828")) +
  labs(title = "Which party held the office of Taoiseach longest?",
       subtitle = "From 1922 to 2021")

pie_chart <- pie_chart + theme_void() + theme(legend.title = element_blank(), 
                                 legend.position = "top",
                                 text = element_text(size = 25))

Migration and GNP trend graph code:

migration_trend <- ire_scale %>% 
  dplyr::filter(!is.na(mig_value)) %>% 
  ggplot() + 
  geom_rect(aes(ymin= 0, ymax = -Inf, xmin =-Inf, xmax =Inf), fill = "#9d0208", colour = NA, alpha = 0.07) +
  geom_rect(aes(ymin= 0, ymax = Inf, xmin =-Inf, xmax =Inf), fill = "#2a9d8f", colour = NA, alpha = 0.07) +
  geom_line(aes(x = year, y = gnp_scale), linetype = "dashed", color = "#457b9d", size = 3.5, alpha = 0.7) +
  geom_line(aes(x = year, y = mig_scale), size = 2.5) +
  labs(title = "Relationship between GNP and net migration in Ireland?",
       subtitle = "From 1960 to 2018")


mig_trend <- migration_trend + 
  annotate(geom = "text", x = 1983, y = 1.3, label = "Net Migration", size = 10, hjust = "left") +
  annotate(geom = "curve", x = 1990, y = 1.4, xend = 2000, yend = 1.5, curvature = -0.3, arrow = arrow(length = unit(0.7, "cm")), size = 3) +
  annotate(geom = "text", x = 1995, y = -1.2, label = "GNP", color = "#457b9d", size = 10, hjust = "left") +
  annotate(geom = "curve", x = 1999, y = -1.1, xend = 2000, color = "#457b9d", yend = -0.1, curvature = 0.3, arrow = arrow(length = unit(0.7, "cm")), size = 3)

mig_trend <- mig_trend  + 
  theme_fivethirtyeight() + 
  scale_y_continuous(name = "Net Migration", labels = comma) +
  bbplot::bbc_style() +
  theme(text = element_text(size = 25))

Download European Social Survey data with essurvey package in R

The European Social Survey (ESS) measure attitudes in thirty-ish countries (depending on the year) across the European continent. It has been conducted every two years since 2001.

The survey consists of a core module and two or more ‘rotating’ modules, on social and public trust; political interest and participation; socio-political orientations; media use; moral, political and social values; social exclusion, national, ethnic and religious allegiances; well-being, health and security; demographics and socio-economics.

So lots of fun data for political scientists to look at.

install.packages("essurvey")
library(essurvey)

The very first thing you need to do before you can download any of the data is set your email address.

set_email("rforpoliticalscience@gmail.com")

Don’t forget the email address goes in as a string in “quotations marks”.

Show what countries are in the survey with the show_countries() function.

show_countries()
[1] "Albania"     "Austria"    "Belgium"           
[4] "Bulgaria"    "Croatia"     "Cyprus"            
[7] "Czechia"     "Denmark"     "Estonia"           
[10] "Finland"    "France"      "Germany"           
[13] "Greece"     "Hungary"     "Iceland"           
[16] "Ireland"    "Israel"      "Italy"             
[19] "Kosovo"     "Latvia"      "Lithuania"         
[22] "Luxembourg" "Montenegro"  "Netherlands"       
[25] "Norway"     "Poland"      "Portugal"          
[28] "Romania" "Russian Federation" "Serbia"            
[31] "Slovakia"   "Slovenia"     "Spain"             
[34] "Sweden"     "Switzerland"  "Turkey"            
[37] "Ukraine"    "United Kingdom"

It’s important to know that country names are case sensitive and you can only use the name printed out by show_countries(). For example, you need to write “Russian Federation” to access Russian survey data; if you write “Russia”…

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Using these country names, we can download specific rounds or waves (i.e survey years) with import_country.  We have the option to choose the two most recent rounds, 8th (from 2016) and 9th round (from 2018).

ire_data <- import_all_cntrounds("Ireland")

The resulting data comes in the form of nine lists, one for each round

These rounds correspond to the following years:

  • ESS Round 9 – 2018
  • ESS Round 8 – 2016
  • ESS Round 7 – 2014
  • ESS Round 6 – 2012
  • ESS Round 5 – 2010
  • ESS Round 4 – 2008
  • ESS Round 3 – 2006
  • ESS Round 2 – 2004
  • ESS Round 1 – 2002

I want to compare the first round and most recent round to see if Irish people’s views have changed since 2002. In 2002, Ireland was in the middle of an economic boom that we called the “Celtic Tiger”. People did mad things like buy panini presses and second house in Bulgaria to resell. Then the 2008 financial crash hit the country very hard.

Irish people during the Celtic Tiger:

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Irish people after the Celtic Tiger crash:

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Ireland in 2018 was a very different place. So it will be interesting to see if these social changes translated into attitude changes.

First, we use the import_country() function to download data from ESS. Specify the country and rounds you want to download.

ire <-import_country(country = "Ireland", rounds = c(1, 9))

The resulting ire object is a list, so we’ll need to extract the two data.frames from the list:

ire_1 <- ire[[1]]

ire_9 <- ire[[2]]

The exact same questions are not asked every year in ESS; there are rotating modules, sometimes questions are added or dropped. So to merge round 1 and round 9, first we find the common columns with the intersect() function.

common_cols <- intersect(colnames(ire_1), colnames(ire_9))

And then bind subsets of the two data.frames together that have the same columns with rbind() function.

ire_df <- rbind(subset(ire_1, select = common_cols),
                subset(ire_9, select = common_cols))

Now with my merged data.frame, I only want to look at a few of the variables and clean up the dataset for the analysis.

Click here to look at all the variables in the different rounds of the survey.

att9 <- data.frame(country = data9$cntry,
                   round = data9$essround,
                   imm_same_eth = data9$imsmetn,
                   imm_diff_eth = data9$imdfetn,
                   imm_poor = data9$impcntr,
                   imm_econ = data9$imbgeco,
                   imm_culture = data9$imueclt,
                   imm_qual_life = data9$imwbcnt,
                   left_right = data9$lrscale)

class(att9$imm_same_eth)

All the variables in the dataset are a special class called “haven_labelled“. So we must convert them to numeric variables with a quick function. We exclude the first variable because we want to keep country name as a string character variable.

att_df[2:15] <- lapply(att_df[2:15], function(x) as.numeric(as.character(x)))

We can look at the distribution of our variables and count how many missing values there are with the skim() function from the skimr package

library(skimr)

skim(att_df)

We can run a quick t-test to compare the mean attitudes to immigrants on the statement: “Immigrants make country worse or better place to live” across the two survey rounds.

Lower scores indicate an attitude that immigrants undermine Ireland’ quality of life and higher scores indicate agreement that they enrich it!

t.test(att_df$imm_qual_life ~ att_df$round)

In future blog, I will look at converting the raw output of R into publishable tables.

The results of the independent-sample t-test show that if we compare Ireland in 2002 and Ireland in 2018, there has been a statistically significant increase in positive attitudes towards immigrants and belief that Ireland’s quality of life is more enriched by their presence in the country.

As I am currently an immigrant in a foreign country myself, I am glad to come from a country that sees the benefits of immigrants!

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If we load the ggpubr package, we can graphically look at the difference in mean attitude scores.

library(ggpubr)

box1 <- ggpubr::ggboxplot(att_df, x = "round", y = "imm_qual_life", color = "round", palette = c("#d11141", "#00aedb"),
 ylab = "Attitude", xlab = "Round")

box1 + stat_compare_means(method = "t.test")

It’s not the most glamorous graph but it conveys the shift in Ireland to more positive attitudes to immigration!

I suspect that a country’s economic growth correlates with attitudes to immigration.

So let’s take the mean annual score values

ire_agg <- ireland[!duplicated(ireland$mean_imm_qual_life),]
ire_agg <- ire_agg %>% 
select(year, everything())

Next we can take data from Quandl website on annual Irish GDP growth (click here to learn how to access economic data via a Quandl API on R.)

gdp <- Quandl('ODA/IRL_LE', start_date='2002-01-01', end_date='2020-01-01',type="raw")

Create a year variable from the date variable

gdp$year <- substr(gdp$Date, start = 1, stop = 4)

Add year variable to the ire_agg data.frame that correspond to the ESS survey rounds.

year =c("2002","2004","2006","2008","2010","2012","2014","2016","2018")
year <- data.frame(year)
ire_agg <- cbind(ire_agg, year)

Merge the GDP and ESS datasets

ire_agg <- merge(ire_agg, gdp, by.x = "year", by.y = "year", all.x = TRUE)

Scale the GDP and immigrant attitudes variables so we can put them on the same plot.

ire_agg$scaled_gdp <- scale(ire_agg$Value)

ire_agg$scaled_imm_attitude <- scale(ire_agg$mean_imm_qual_life)

In order to graph both variables on the same graph, we turn the two scaled variables into two factors of a single variable.

ire_agg <- ire_agg %>%
  select(year, scaled_imm_attitude, scaled_gdp) %>%
  gather(key = "variable", value = "value", -year)

Next, we can change the names of the factors

ire_agg$variable <- revalue(ire_agg$variable, c("scaled_gdp"="GDP (scaled)", "scaled_imm_attitude" = "Attitudes (scaled)"))

And finally, we can graph the plot.

The geom_rect() function graphs the coloured rectangles on the plot. I take colours from this color-hex website; the green rectangle for times of economic growth and red for times of recession. Makes sure the geom-rect() comes before the geom_line().

library(ggpthemes)

ggplot(ire_agg, aes(x = year, y = value, group = variable)) + geom_rect(aes(xmin= "2008",xmax= "2012",ymin=-Inf, ymax=Inf),fill="#d11141",colour=NA, alpha=0.01) +
  geom_rect(aes(xmin= "2002" ,xmax= "2008",ymin=-Inf, ymax=Inf),fill="#00b159",colour=NA, alpha=0.01) +
  geom_rect(aes(xmin= "2012" ,xmax= "2020",ymin=-Inf, ymax=Inf),fill="#00b159",colour=NA, alpha=0.01) +
  geom_line(aes(color = as.factor(variable), linetype = as.factor(variable)), size = 1.3) + 
  scale_color_manual(values = c("#00aedb", "#f37735")) + 
  geom_point() +
  geom_text(data=. %>%
              arrange(desc(year)) %>%
              group_by(variable) %>%
              slice(1), aes(label=variable), position= position_jitter(height = 0.3), vjust =0.3, hjust = 0.1, 
              size = 4, angle= 0) + ggtitle("Relationship between Immigration Attitudes and GDP Growth") + labs(value = " ") + xlab("Year") + ylab("scaled") + theme_hc()

And we can see that there is a relationship between attitudes to immigrants in Ireland and Irish GDP growth. When GDP is growing, Irish people see that immigrants improve quality of life in Ireland and vice versa. The red section of the graph corresponds to the financial crisis.