# List of packages
packages <- c("tidyverse", "infer", "broom", "fst", "modelsummary", "effects", "survey", "interactions") 

# Install packages if they aren't installed already
new_packages <- packages[!(packages %in% installed.packages()[,"Package"])]
if(length(new_packages)) install.packages(new_packages)

# Load the packages
lapply(packages, library, character.only = TRUE)
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Task 1

Graph the histogram distribution using the populist scale (as we did in the tutorial) for the country of Sweden. What do you note?

# Setting values greater than 10 to NA
sweden_data<- read.fst("sweden_data.fst")

sweden_data$trstplt <- ifelse(sweden_data$trstplt > 10, NA, sweden_data$trstplt)
sweden_data$trstprl <- ifelse(sweden_data$trstprl > 10, NA, sweden_data$trstprl)
sweden_data$trstprt <- ifelse(sweden_data$trstprt > 10, NA, sweden_data$trstprt)

# Creating and rescaling the trust variable
sweden_data$trust <- scales::rescale(sweden_data$trstplt + sweden_data$trstprl + sweden_data$trstprt, na.rm = TRUE, to = c(0, 100))

sweden_data$populist <- scales::rescale(sweden_data$trust, na.rm = TRUE, to=c(100,0))
ggplot(sweden_data, aes(x = populist)) +
  geom_histogram(bins = 30, fill = "blue", color = "black") +
  theme_minimal() +
  labs(title = "Distribution of Populist Scale for Sweden",
       x = "Populist Scale",
       y = "Count")
## Warning: Removed 2503 rows containing non-finite values (`stat_bin()`).

According to Norris and Inglehart’s populist scale, a score of 0 indicates complete trust in parliament and/or politicians, whereas a score of 100 indicates complete distrust in parliament/ politicans. The histogram created for Sweden indicates greater peaks around the 25-50 range compared to the 50-100 range. This indicates that there is a significant portion of the population that falls within the category of having moderate trust in parliament/ politicians due to the peak being at 50.

Task 2

Run a linear regression with populist attitudes as the outcome, educational attainment (recoded as a binary “BA or more” and “No BA”), and using the Swedish data. Print the intercept and coefficients only and interpret. Then do a tidy model table displaying the p-value (with digits = 3) and interpret.

sweden_data <- sweden_data %>%
  mutate(
 # Recoding education
    educ.ba = case_when(
      essround < 5 & edulvla == 5 ~ "BA or more",
      essround >= 5 & edulvlb > 600 ~ "BA or more",
      TRUE ~ "No BA"
    ),
    
    # Handle NAs for education levels
    edulvla = ifelse(edulvla %in% c(77, 88, 99), NA_integer_, edulvla),
    edulvlb = ifelse(edulvlb %in% c(5555, 7777, 8888), NA_integer_, edulvlb),
    
    # Explicitly making 'No BA' the reference category
    educ.ba = factor(educ.ba, levels = c("No BA", "BA or more")),
  )
table(sweden_data$educ.ba)
## 
##      No BA BA or more 
##      13477       4739
sweden_pop_model <- lm(populist ~ educ.ba, data = sweden_data)

coefficients_sweden <- coef(sweden_pop_model)
print(coefficients_sweden)
##       (Intercept) educ.baBA or more 
##         51.358680         -7.868121

Intercept (51.4):

-This value represents the average score on the populist scale for the reference group in Sweden, which is individuals with “no BA”. The expected average populist scale score would be 51.4 for those that have a lower educational attainment or “no BA”.This score indicates a certain level of populism. Scores higher than this, indicate greater and stronger populist attitudes.

educ.baBA or more Coefficient (-7.9):

-The negative coefficient associated with the educational attainment of “BA or more” group, on average are individuals that have populist scale scores that are 7.9 points lower than those with “no BA”. This indicates that individuals with “no BA” exhibit stronger populist attitudes compared to those with “BA or more”.

tidy(sweden_pop_model) |>
knitr::kable(digits = 3)
term estimate std.error statistic p.value
(Intercept) 51.359 0.181 283.363 0
educ.baBA or more -7.868 0.350 -22.494 0
summary(sweden_pop_model)
## 
## Call:
## lm(formula = populist ~ educ.ba, data = sweden_data)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -51.359 -14.692  -1.359  11.975  56.509 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)        51.3587     0.1812  283.36   <2e-16 ***
## educ.baBA or more  -7.8681     0.3498  -22.49   <2e-16 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 19.43 on 15711 degrees of freedom
##   (2503 observations deleted due to missingness)
## Multiple R-squared:  0.0312, Adjusted R-squared:  0.03114 
## F-statistic:   506 on 1 and 15711 DF,  p-value: < 2.2e-16

P-Value Interpretation:

-The p-value indicates that it is statistically significant.

Task 3

Now using the Italian dataset and the authoritarian values scale (as we did in the tutorial), graph the average by survey year. Interpret.

df <- read.fst("italy_data.fst")
df <- df %>%
  mutate(behave = ipbhprp,
         secure = impsafe,
         safety = ipstrgv,
         tradition = imptrad,
         rules = ipfrule) %>%
  mutate(across(c("behave", "secure", "safety", "tradition", "rules"),
                ~ na_if(.x, 7) %>% na_if(8) %>% na_if(9))) %>%
  mutate(across(c("behave", "secure", "safety", "tradition", "rules"), ~ 7 - .x ))

df$auth <- scales::rescale(df$behave + 
                      df$secure + 
                      df$safety + 
                      df$tradition + 
                      df$rules, to=c(0,100), na.rm=TRUE)


df <- df %>% filter(!is.na(auth))
table(df$secure)
## 
##    1    2    3    4    5    6 
##   54  139  626 1856 2876 2881
table(df$auth)
## 
##   0  12  16  20  24  28  32  36  40  44  48  52  56  60  64  68  72  76  80  84 
##   7   4   4   9  13  20  27  57 113 155 163 323 367 596 647 789 823 897 992 733 
##  88  92  96 100 
## 632 465 299 297
df$year <- NA
replacements <- c(2002, 2004, 2006, 2008, 2010, 2012, 2014, 2016, 2018, 2020)
for(i in 1:10){
  df$year[df$essround == i] <- replacements[i]
}
auth_avg <- df %>%
  group_by(year) %>%
  summarize(auth_avg = mean(auth, na.rm = TRUE))

plot_auth <- ggplot(auth_avg, aes(x = year, y = auth_avg)) +
  geom_point(aes(color = auth_avg), alpha = 1.0) + 
  geom_line(aes(group = 1), color = "blue", linetype = "dashed") +  
  labs(title = "Authoritarian Scale Average by Year (Italy)",
       x = "Survey Year",
       y = "Authoritarian Scale Average") +
  theme_minimal() +
  theme(legend.position = "none") +
  scale_y_continuous(limits = c(0, 100))

print(plot_auth)

Interpretation: The authoritarian scale average in Italy decreses very little from the years 2012 to 2020. There are no significant changes, and can be interpreted as a pretty stable graph.

Task 4

Now run a linear regression model, using the modelsummary package, with authoritarian values as the outcome, and generations as the predictor/potential explanatory variable, and using the Italian data again. Rename the coefficients using the coef_rename function. Interpret the coefficients, whether they are statistically significant, and the adjusted R-squared.

df <- read.fst("italy_data.fst")
df <- df %>%
  mutate(behave = ipbhprp,
         secure = impsafe,
         safety = ipstrgv,
         tradition = imptrad,
         rules = ipfrule) %>%
  mutate(across(c("behave", "secure", "safety", "tradition", "rules"),
                ~ na_if(.x, 7) %>% na_if(8) %>% na_if(9))) %>%
  mutate(across(c("behave", "secure", "safety", "tradition", "rules"), ~ 7 - .x ))

df$auth <- scales::rescale(df$behave + 
                      df$secure + 
                      df$safety + 
                      df$tradition + 
                      df$rules, to=c(0,100), na.rm=TRUE)


df <- df %>% filter(!is.na(auth))
table(df$secure)
## 
##    1    2    3    4    5    6 
##   54  139  626 1856 2876 2881
model_data <- df %>%
  mutate(
    cohort = ifelse(yrbrn < 1930 | yrbrn > 2000, NA, yrbrn),

    gen = case_when(
      yrbrn %in% 1900:1945 ~ "1",
      yrbrn %in% 1946:1964 ~ "2",
      yrbrn %in% 1965:1979 ~ "3",
      yrbrn %in% 1980:1996 ~ "4",
      TRUE ~ as.character(cohort)  
    ),
    gen = factor(gen,
                 levels = c("1", "2", "3", "4"),
                 labels = c("Interwar", "Baby Boomers", "Gen X", "Millennials"))
  )
table(model_data$gen)
## 
##     Interwar Baby Boomers        Gen X  Millennials 
##         1026         2580         2214         1811
model1 <- lm(auth ~ gen, data = model_data)
modelsummary(
  list(model1),
  fmt = 1,
  estimate  = c( "{estimate} ({std.error}){stars}"),
  statistic = NULL,
  coef_rename = c("genBaby Boomers"= "Baby Boomers", "genGen X"= "Gen X", "genMillennials"= "Millennials"),
  coef_omit = "Intercept")
 (1)
Baby Boomers −1.1 (0.6)*
Gen X −2.1 (0.6)***
Millennials −3.6 (0.6)***
Num.Obs. 7631
R2 0.006
R2 Adj. 0.006
AIC 62934.0
BIC 62968.7
Log.Lik. −31462.009
RMSE 14.94

Coefficient:

-Baby Boomers (-1.1, p<0.001): They exhibit scores that are, on average, 1.1 points lower on the authoritarian values scale, in comparison to the Interwar generation (a category that is omitted). The single asterisk generally denotes that the coefficient is statistically significant at the 0.05 level.

-Gen X (-2.1, p<0.001): Gen X shows a striking decrease, with scores that are 2.1 points lower than the Interwar generation on the authoritarian values scale. The triple asterisks denotes significance at the 0.001 level.

-Millennials (-3.6, p<0.001): Millennials exhibit the most considerable decrease in authoritarian values, with their scores being 3.6 points lower than those of the Interwar generation. Once again, the triple asterisks denotes significance at the 0.001 level.

R-squared Adjusted (0.006):The adjusted R-squared value of 0.006 means that the ‘gen’ variable (with our four coded generations) explain approximately 0.6% of the variance in the authoritarian values scale for Italy. This suggests that the model explains only a small portion of the variability in authoritarian values, pointing to other factors outside of generational differences that may impact and shape attitudes.

Task 5

Now visualize, using the modelplot() function from the modelsummary package, coefficient estimates and 95% confidence intervals for the following three models:

Model 1 = populist attitudes scale as the outcome; left/right as the single predictor (omitting moderates as we did in the tutorial), and using data for Greece.

Model 2 = populist attitudes scale as the outcome; gender as the single predictor, and using data for Greece.

Model 3 = populist attitudes scale as the outcome; generations as the single predictor (using the four generational category recode we did in the tutorial), and using data for Greece. Interpret.

greece_data<- read.fst("greece_data.fst")
greece_data$trstplt <- ifelse(greece_data$trstplt > 10, NA, greece_data$trstplt)
greece_data$trstprl <- ifelse(greece_data$trstprl > 10, NA, greece_data$trstprl)
greece_data$trstprt <- ifelse(greece_data$trstprt > 10, NA, greece_data$trstprt)

greece_data$trust <- scales::rescale(greece_data$trstplt + greece_data$trstprl + greece_data$trstprt, na.rm = TRUE, to = c(0, 100))

greece_data$populist <- scales::rescale(greece_data$trust, na.rm = TRUE, to=c(100,0))
model_data <- greece_data %>%
  mutate(
    # Recoding gender
    gndr = case_when(
      gndr == 1 ~ "Male",
      gndr == 2 ~ "Female",
      gndr == 9 ~ NA_character_,
      TRUE ~ as.character(gndr)
    ),

     lrscale= case_when(
      lrscale %in% 0:4~ "Left", 
      lrscale %in% 6:10 ~ "Right",
      lrscale %in% c(77, 88, 99) ~ NA_character_,
      TRUE~ NA_character_
    ),

    # Recoding age, setting 999 to NA
    age = ifelse(agea == 999, NA, agea),

    # Recoding cohort variable, setting years before 1930 and after 2000 to NA
    cohort = ifelse(yrbrn < 1930 | yrbrn > 2000, NA, yrbrn),

    # Recoding generational cohorts based on year of birth
    gen = case_when(
      yrbrn %in% 1900:1945 ~ "1",
      yrbrn %in% 1946:1964 ~ "2",
      yrbrn %in% 1965:1979 ~ "3",
      yrbrn %in% 1980:1996 ~ "4",
      TRUE ~ as.character(cohort)  # Keeping other values as character if they do not fit the ranges
    ),

    # Converting cohort to a factor with labels
    gen = factor(gen,
                 levels = c("1", "2", "3", "4"),
                 labels = c("Interwar", "Baby Boomers", "Gen X", "Millennials"))
  )
models <- list(
   "Model 1" = lm(populist ~ lrscale, data = model_data),
   "Model 2" = lm(populist ~ gndr, data = model_data),
   "Model 3" = lm(populist ~ gen, data = model_data))
modelsummary(models, fmt = 1,
  estimate  = c("{estimate} ({std.error}){stars}",
                "{estimate} ({std.error}){stars}",
                "{estimate} ({std.error}){stars}"),
  statistic = NULL)
Model 1  Model 2  Model 3
(Intercept) 72.0 (0.5)*** 70.0 (0.3)*** 65.8 (0.5)***
lrscaleRight −8.8 (0.6)***
gndrMale −1.0 (0.5)*
genBaby Boomers 3.5 (0.7)***
genGen X 5.6 (0.7)***
genMillennials 5.8 (0.7)***
Num.Obs. 4936 9823 9562
R2 0.037 0.000 0.009
R2 Adj. 0.036 0.000 0.009
AIC 44723.8 88873.2 86473.9
BIC 44743.3 88894.8 86509.7
Log.Lik. −22358.894 −44433.590 −43231.944
RMSE 22.44 22.30 22.25
modelplot(models, coef_omit = 'Interc')

Interpretation:

-genBaby Boomers (3.5):Compared to the Interwar generation (reference category that is omitted), baby boomers exhibit scores that are, on average, 3.5 points higher on the authoritarian values scale (0-100). The triple asterisk denotes significance at the 0.001 level.

-genGen X (5.6): Gen X shows a greater increase compared to the baby boomers, with scores 5.6 points higher than the Interwar generation on the authoritarian values scale. The triple asterisk denotes significance at a very low level (0.001).

-genMillennials (5.8): Millennials exhibit the most considerable increase when in comparison to baby boomers and Gen X in authoritarian values, with scores 5.8 points higher than the Interwar generation on the scale. The triple asterisks denotes significance at a very low level (0.001).

-R-Squared Adjusted (0.036): The adjusted r-squared value of 0.036 means that the ‘gen’ variable explains approx. 3.6% of the variance when it comes to the authoritarian values scale for Greece.